CN112539093A

CN112539093A - Valve timing and lift variable device for internal combustion engine and adjusting mode thereof

Info

Publication number: CN112539093A
Application number: CN202011412430.6A
Authority: CN
Inventors: 沈大兹; 罗宝军; 谯俊豪
Original assignee: Hunan Dazi Power Technology Co ltd
Current assignee: Hunan Dazi Power Technology Co ltd
Priority date: 2020-12-03
Filing date: 2020-12-03
Publication date: 2021-03-23

Abstract

The present invention provides a valve timing and lift variable device for an internal combustion engine, including: the device comprises a first cam shaft, a second cam shaft, at least one lever assembly, limiters and return springs, wherein the quantity of the limiters and the return springs is the same as that of the lever assemblies, and at least one phaser; the valve timing and the valve lift are continuously changed by adjusting the first camshaft and/or adjusting the second camshaft through the phaser, so that the Miller cycle of early closing and late closing is conveniently realized, and the impact force at the opening and closing time of the valve is minimized.

Description

Valve timing and lift variable device for internal combustion engine and adjusting mode thereof

Technical Field

The invention relates to a variable valve timing and lift device for an internal combustion engine, in particular to a Miller cycle suitable for various reciprocating piston type internal combustion engines to realize early valve closing and/or late valve closing.

Background

Variable Valve Timing (VVT) and Variable Valve Lift (VVL) technologies have been widely used in internal combustion engines, and have a great effect on improving the performance of the internal combustion engines.

Many VVL technologies can achieve a miller cycle with early valve closing, but cannot achieve a miller cycle with late valve closing at the same time, and cannot achieve satisfactory results in terms of engine performance.

In addition, the valve is required to be set at the joint of the buffer section and the working section of the cam profile at the opening and closing time, so that the impact when the valve is opened and closed can be reduced, and the vibration and the noise can be inhibited. However, for most existing VVLs, the above requirements can be met only when the maximum valve lift is operating. Because the valve lift can be changed, in most cases, the opening and closing time of the valve lift occurs in the working section of the cam profile, and because the speed and the acceleration of the working section of the cam profile are large, the vibration and the noise of the cam mechanism are obviously increased. US8,113,158 discloses a mechanism mounted coaxially by two camshafts, but this structure is not strong enough, has a small range of adjustment angles, and cannot achieve miller cycle of early closing or late closing at the same time.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, improve the adjusting range of the timing and/or the lift, reduce the operation vibration and the noise, improve the reliability of the device and provide the variable valve timing and/or valve lift device which can completely meet the performance requirements of the internal combustion engine and can be adjusted in a wider range.

The embodiment provides a valve timing and lift variable device for an internal combustion engine, including: first camshaft, second camshaft, at least one lever subassembly, the stopper and reset spring the same with lever subassembly quantity, first phaser and second phaser, its characterized in that:

the first camshaft and the second camshaft are rotatably arranged on a cylinder cover of the internal combustion engine in parallel but not coaxial, and are synchronously rotated through gear engagement or chain wheel coupling; the front end of the first camshaft is provided with a first phaser which can adjust the timing phase of the first camshaft; the rear end of the second camshaft is provided with a second phase device which can adjust the timing phase of the second camshaft; the first camshaft has at least one first cam and the second camshaft has at least one second cam;

the lever assembly manages two valves of one cylinder and comprises a lever, two first driven wheels, one second driven wheel, a pin shaft, a positioning ring, two rocker arms and two hydraulic tappets;

the hydraulic tappet is arranged on the cylinder cover, so that a connecting line formed by the spherical centers of the two hydraulic tappets is parallel to the first cam shaft and the second cam shaft; one end of the rocker arm is provided with a socket, and the socket is superposed and hinged with the spherical center of the hydraulic tappet; the other end of the rocker arm is in lap joint with the top of the valve; two ends of the pin shaft are respectively inserted in the middle parts of the two rocker arms; the rocker arm can swing by an angle theta around the sphere center, the swing of the rocker arm drives the lever to swing between a position 1 and a position 2 around the sphere center, the position 1 corresponds to a valve zero lift position, namely a valve lift L is equal to 0, the valve is in a closed position, the position 2 corresponds to a valve lift maximum position, namely a valve lift L is equal to Lmax, and the valve is in a maximum opening position;

the lever is sleeved with the pin shaft at the middle fulcrum, and a positioning ring is sleeved between the pin shaft and the lever, so that the lever can swing around the pin shaft; a first driven wheel and a second driven wheel are respectively and rotatably arranged at two ends of the lever; when the lever is positioned at the position 1, the excircle of the positioning ring is in contact with the limiting point through the limiting stopper, and the further swing of the lever is limited through the limiting stopper;

the first cam is in rollable contact with a first driven wheel, and the second cam is in rollable contact with a second driven wheel; when the first cam shaft and the second cam shaft rotate, the first cam and the second cam respectively force the first driven wheel and the second driven wheel which are contacted with the first cam and the second cam to displace, so that a lever fulcrum which is connected with the first driven wheel and the second driven wheel into a whole is displaced, the displacement of the lever fulcrum causes the lever to swing around the spherical center, and therefore, the valve is forced to swing between a position 1 and a position 2, and the opening and the closing of the valve are formed.

Further, the profile curves of the two cams together determine the lift curve of the valve, wherein: the rising buffer section and the rising working section of the first cam profile curve are used for managing the rising section of the valve lift curve, and the opening time and the valve lift of the valve can be changed by adjusting the rotation phase of the first cam; the descending buffer section and the descending working section of the second cam profile curve are used for managing the descending section of the valve lift curve, and the closing time of the valve and the size of the valve lift can be changed by adjusting the rotation phase of the second cam; by adjusting the rotational phase of the first cam and the second cam simultaneously, the opening time, the closing time, the magnitude of the lift and/or the valve opening duration of the valve can be changed.

Furthermore, the first cam shaft, the second cam shaft, a phaser, at least one lever assembly, limiters and return springs are the same as the lever assemblies in number; the method is characterized in that:

the first camshaft and the second camshaft are rotatably arranged on a cylinder cover of the internal combustion engine in parallel but not coaxial, and are synchronously rotated through gear engagement or chain wheel coupling; the rear end of the second camshaft is provided with a phaser, and the phaser can adjust the timing phase of the second camshaft;

the hydraulic tappet is arranged on the cylinder cover, so that a connecting line formed by the spherical centers of the two hydraulic tappets is parallel to the first cam shaft and the second cam shaft; one end of the rocker arm is provided with a socket, and the socket is superposed and hinged with the spherical center of the hydraulic tappet; the other end of the rocker arm is in lap joint with the top of the valve; two ends of the pin shaft are respectively inserted in the middle parts of the two rocker arms; the rocker arm can swing around the center of a sphere by an angle theta, the swing of the rocker arm drives the lever to swing around the center of the sphere between a position 1 and a position 2, wherein the position 1 corresponds to a valve zero lift position (L is 0), namely a valve closing position, and the position 2 corresponds to a valve maximum lift position (L is Lmax), namely a valve maximum opening position;

Preferably, the profile curves of the two cams jointly determine a lift curve of the valve, the closing time of the valve, the magnitude of the valve lift and the valve opening duration can be changed by adjusting the rotation phase of the second cam through a phaser, and the valve opening time can also be delayed by an epsilon angle in a small load area of the internal combustion engine, wherein the maximum value of the epsilon angle does not exceed 10 degrees of cam angle.

Preferably, the second cam phase is advanced to form a miller cycle of early closing of the internal combustion engine, and the second cam phase advance angle is up to 70 degrees of cam rotation angle; the second cam is retarded in phase to form a miller cycle of late closing of the internal combustion engine, the second cam retardation angle being at most 30 cam degrees.

Preferably, no matter how the lift is changed, the valve is always opened when the first cam ascending buffer section end point/ascending working section initial point contacts with the first driven wheel, and the valve is always closed when the second cam descending buffer section end point/descending buffer section initial point contacts with the second driven wheel, so that the impact force generated when the valve is opened and closed is reduced to the maximum.

Preferably, it is characterized in that: the rear end of the first cam shaft is provided with a first gear, the second phase device is provided with a second gear, and the first gear and the second gear form a gear pair which can enable the first cam shaft and the second cam shaft to synchronously rotate in opposite directions.

Preferably, a first gear is mounted to a rear end of the first camshaft, and the phaser has a second gear, the first gear and the second gear forming a gear pair capable of synchronously rotating the first camshaft and the second camshaft in opposite directions.

Preferably, the exhaust camshaft is mounted by a first sprocket and the second phaser has a second sprocket, the two sprockets being coupled using a chain to rotate the first camshaft synchronously and co-directionally with the second camshaft.

Preferably, the exhaust camshaft is mounted with a first sprocket and the phaser has a second sprocket, the two sprockets being coupled using a chain to cause the first camshaft to rotate in synchronism with the second camshaft in the same direction.

Preferably, the return spring may be a torsion spring and/or a spiral spring, one end of which is fixedly installed on the cylinder head and the other end of which overlaps with one end of the lever, which keeps the first driven wheel in contact with the first cam at all times or keeps the second driven wheel in contact with the second cam at all times.

Preferably, the first phaser is a hydraulic or electric phaser and the second phaser is a hydraulic or electric phaser.

Preferably, the phaser is a hydraulic or electric phaser.

Preferably, the valve timing and lift variable device for the internal combustion engine can be applied to a single-cylinder in-line multi-cylinder V-type internal combustion engine

The invention has the beneficial effects that:

(1) the variable valve timing and lift device can realize Miller cycle of early closing and/or late closing and can also realize the valve timing and lift requirement at any position on the MAP of the internal combustion engine;

(2) no matter how the lift of the valve changes, the valve is always kept to be opened and closed in the cam buffering section, so that the impact when the valve is opened can be reduced, and the impact when the valve is closed and seated can also be reduced;

(3) the first cam shaft and the second cam shaft are of traditional integral structures, the strength and the rigidity of the first cam shaft and the second cam shaft are fully verified, and the device is reliable and durable;

(4) the position of the lever can be reliably limited by the limiting device arranged on the cylinder cover, the precision requirement in mass production is ensured, and the organization and production are convenient;

(5) the valve lift is very convenient to adjust at the opening and closing time of the valve, and the performance requirement of the internal combustion engine can be completely met.

Description of the drawings:

FIG. 1 is an isometric view of a valve timing and lift variable device of the present invention;

FIG. 2 is a mounting diagram of a variable valve timing and lift apparatus of the present invention;

FIG. 3 is an isometric view of the lever assembly;

FIG. 4 is a cross-sectional view of a valve closed position and a maximum lift position;

FIG. 5 is a cross-sectional view of the lever positioning;

FIG. 6 is a schematic illustration of maximum lift operation;

FIG. 7 is a second cam phase advance adjustment schematic;

FIG. 8 is a schematic illustration of mid-lift operation;

FIG. 9 is a second cam phase retard adjustment schematic;

FIG. 10 is a schematic illustration of lift operation with extended valve open duration;

FIG. 11 is a schematic illustration of the first cam retarded back by phase angle α;

FIG. 12 is a Miller cycle valve profile for early engine shut-down;

FIG. 13 is a Miller cycle valve profile for late engine closing;

FIG. 14 is a lift profile with the first cam and the second cam simultaneously advanced and simultaneously retarded;

FIG. 15 is a first cam retard opening lift curve;

FIG. 16 is the function of the return spring;

FIG. 17 is a schematic illustration of a phaser adjusting timing and lift;

fig. 18 is a schematic view of a sprocket drive mode of operation.

Wherein:

1, a first camshaft 6, a first phaser 11, a second cam

2, a second cam shaft 7, a second phase device 12, a lever 15 and a pin shaft

3, a lever component 8, a first gear 13, a first driven wheel 16 and a positioning ring

4, a limiter 9, a second gear 17 and a rocker arm

5, a return spring 10, a first cam 14, a second driven wheel 18 and a hydraulic tappet

19, a sphere center 23, a limit point 30 and a phase device

20, air valve 24, original line. 27, first sprocket

21, top 25, new line 28, second sprocket

22, fulcrum 26, exhaust cam shaft 29, chain

Detailed Description

Example 1:

embodiment 1 of the present invention will be described in detail below with reference to fig. 1 to 16.

As shown in fig. 1, this example provides a valve timing and lift variable device including: the camshaft phaser comprises a first camshaft 1, a second camshaft 2, at least one lever assembly 3, a limiter 4, a return spring 5, a first phaser 6 and a second phaser 7;

as shown in fig. 2, the first camshaft 1 and the second camshaft 2 are rotatably mounted on a cylinder head (not shown) of an internal combustion engine in parallel but not coaxially, and the first camshaft 1 and the second camshaft 2 are synchronously rotated in opposite directions by a first gear 8 mounted on the rear end of the first camshaft 1 meshing with a second gear 9 mounted on a second phaser 7; a first phaser 6 is mounted on the front end of the first camshaft 1 (as viewed from the front end of the internal combustion engine), the first phaser 6 being capable of adjusting the timing phase of the first camshaft 1; a second phase device 7 is installed at the rear end of the second camshaft 2, and the second phase device 7 can adjust the timing phase of the second camshaft 2; the first camshaft 1 has at least one first cam 10 and the second camshaft 2 has at least one second cam 11.

As shown in fig. 3, the lever assembly 3 manages two valves 20 of one cylinder, and includes a lever 12, two first driven wheels 13, one second driven wheel 14, a pin 15, a positioning ring 16, two rocker arms 17, and two hydraulic tappets 18;

referring to fig. 4, the hydraulic tappets 18 are mounted on the cylinder head such that a line formed by the centers 19 of the two hydraulic tappets 18 is parallel to the first camshaft 1 and the second camshaft 2; one end of the rocker arm 17 has a socket which coincides with and is hinged to the spherical centre 19 of the hydraulic tappet 18; the other end of the rocker arm 17 is overlapped with the top 21 of the valve 20; two ends of the pin shaft 15 are respectively inserted in the middle parts of the two rocker arms 17; the rocker arm 17 can swing around the center 19 by an angle θ, and the swing of the rocker arm 17 swings the lever 12 around the center 19 between a position 1 (fig. 4a) and a position 2 (fig. 4b), where the position 1 corresponds to a valve zero lift position (L ═ 0), i.e., a valve closing position, and the position 2 corresponds to a valve lift maximum position (L ═ Lmax), i.e., a valve maximum opening position.

As shown in fig. 5, the lever 12 is sleeved on the pin 15 at a middle pivot 22, and a positioning ring 16 is sleeved between the pin and the pin, so that the lever 12 can swing around the pin 15; a first driven wheel 13 and a second driven wheel 14 are respectively and rotatably arranged at two ends of the lever 12; when the lever 12 is at the position 1, the outer circle of the positioning ring 16 is contacted with the stopper 4 at a limit point 23, and the stopper 4 limits the lever 12 to further swing around the spherical center 19;

the first cam 10 and the second cam 11 are respectively in rolling contact with a first driven wheel 13 and a second driven wheel 14; when the first camshaft 1 and the second camshaft 2 rotate, the first cam 10 and the second cam 11 respectively force the first driven wheel 13 and the second driven wheel 14 in contact with the first cam to displace, so that the lever fulcrum 22 connected with the first driven wheel 13 and the second driven wheel 14 is displaced, the displacement of the lever fulcrum 22 causes the lever 12 to swing around the spherical center 19, so that the valve 20 is forced to swing between the position 1 and the position 2, and the opening and the closing of the valve are formed.

Fig. 6 is a schematic diagram of maximum lift operation, where the first cam 10 is distributed circumferentially at A, B, C, D and E, where: E-A is a small base circle section, A-B is an ascending buffer section, B-C is an ascending working section, C-D is a large base circle section, D-E is a descending working section, and F is one point in the large base circle section C-D. The second cam 11 is circumferentially distributed with points a ', B ', C ', D ' and E ', wherein: e ' -A ' is a small base circle segment, A ' -B ' is an ascending segment, B ' -C ' is a large base circle segment, C ' -D ' is a descending working segment, D ' -E ' is a descending buffering segment, and F ' is a point on the large base circle segment B ' -C '.

As shown in fig. 6a, the fulcrum 22 of the setting lever 12 is at position 1, i.e. the valve lift is at zero lift, the first driven wheel 13 contacts the first cam 10 at point B, and the second driven wheel 14 contacts the second cam 11 at point F'. At this time, the first driven wheel 13 rolls from point a to point B through the lift buffer, so that the first driven wheel 13 is displaced downward by a slight amount, and the slight amount of displacement completely eliminates the minute gap between the parts of the lever 12, and the valve 20 reaches a position immediately before opening but not yet opening.

As shown in fig. 6B, when the first cam 10 rotates clockwise from point B to point C along the ascending operation section, the second cam 11 rotates counterclockwise from point F 'to point C' along the large base circle section, the first driven wheel 13 is pressed by the ascending operation section of the first cam 10 to displace downward, the second driven wheel 14 rolls along the large base circle section of the second cam 11 without radial displacement, the lever fulcrum 22 is displaced along with the displacement of the first driven wheel 13, the lever 12 is forced to swing downward around the spherical center 19, and the valve 20 is forced to open until the fulcrum 22 of the lever 12 reaches the position 2, and the corresponding valve 20 reaches the maximum lift position (L ═ Lmax).

As shown in fig. 6C, further, when the first cam 10 rotates clockwise from point C to point F along the major base circle segment of the first cam 10, and simultaneously the second cam 11 rotates counterclockwise correspondingly from point C 'to point D' along the descending operation segment, the first driven wheel 13 rolls on the major base circle segment of the first cam 10 without radial displacement; the second driven wheel 14 is driven by the valve spring force W to displace upwards, the lever fulcrum 22 displaces along with the displacement of the second driven wheel 14, the pushing force of the valve spring force W forces the lever 12 to swing upwards around the spherical center 19 until the fulcrum 22 of the lever 12 reaches the position 1, and the valve 20 is forced to close until the position of zero valve lift is reached.

Further, in order to avoid an excessive impact force when the valve 20 is seated, when the valve lift reaches the zero lift position, the contact point of the second cam 11 with the second follower 14 just enters the descent buffer start point D' of the second cam 11.

In conclusion, no matter the opening time or the closing time, the contact point position of the driven wheel and the cam is in the buffer section, and the impact force at the opening time and the closing time is greatly reduced.

Fig. 7 is a phase advance adjustment diagram of the second cam 11. Fig. 7a shows the phase of the first cam 10 and the second cam 11 before adjustment, and fig. 7b shows the second cam 11 after adjustment rotating by an angle Φ in the advance direction, at this time, both fig. 7a and fig. 7b are the time when the valve is about to open but not open, and the fulcrum 22 of the lever 12 is at position 1.

FIG. 8 is a schematic illustration of mid-lift operation. On the basis of fig. 6a, the second cam 11 is adjusted clockwise by an angle Φ in the advance direction, which evolves to fig. 8a, where: Φ is referred to as the second cam 11 phase advance angle.

As shown in fig. 8a, the fulcrum 22 of the setting lever 12 is at position 1, i.e. the valve lift is at zero lift, the first driven wheel 13 contacts with the first cam 10 at point B, the second driven wheel 14 contacts with the second cam 11 at point G ', and G' is a point on the large base circle segment B '-C'.

As shown in fig. 8B, further, when the first cam 10 rotates clockwise from point B to point C along the ascending operation segment, the second cam 11 rotates counterclockwise correspondingly from point G 'to point H' along the large base circle segment, wherein: h ' is a point in the descending operating section C ' -D '. The first driven wheel 13 is pressed by the ascending operation section of the first cam 10 to move downwards, the second driven wheel 14 rolls along the descending operation section of the second cam 11 to move upwards, the lever fulcrum 22 moves along with the displacement of the first driven wheel 13 and the second driven wheel 14, the lever 12 is forced to swing downwards around the center of a sphere, and the valve 20 is forced to open until the lever fulcrum 22 reaches a certain middle position (L is equal to M), and the corresponding valve 20 also reaches a certain middle position.

Further, as shown in fig. 8C, when the first cam 10 rotates clockwise from point C to point G along the large base circle segment of the cam 1, the second cam 11 simultaneously rotates counterclockwise correspondingly and synchronously from point H 'to point D' along the descending operation segment, wherein: the point G is one of the large base circle sections C-D of the first cam 10, and the first driven wheel 13 rolls on the large base circle section of the first cam 10 without radial displacement; the driven wheel 11 is driven by the valve spring force W to displace upwards, the lever fulcrum 22 displaces along with the displacement of the driven wheel 11, the pushing force of the valve spring force W forces the lever 12 to swing upwards around the sphere center until the lever fulcrum 22 reaches the position 1, and the valve 20 is forced to close until the position of zero valve lift is reached.

In summary, when the phase advance angle Φ of the second cam 11 increases, the valve lift decreases, the valve closing time advances by an angle Φ, and the corresponding valve opening duration also decreases by an angle Φ.

Therefore, the valve lift adjusting device has the advantages that at any time of valve lift adjustment, the valve is opened and closed in the buffer section, namely the valve has the characteristic of minimum impact force; and with the continuous increase of the phase advance angle phi of the second cam 11, the valve lift is continuously reduced until the valve lift is zero, meanwhile, the valve closing time is also continuously advanced, and the valve opening duration is continuously shortened until the valve opening duration is zero.

The phase advance angle Φ of the second cam 11 of the present embodiment is 70 degrees cam rotation angle at maximum.

Fig. 9 is a schematic diagram of the phase delay adjustment of the second cam 11. In fig. 9a, the phases of the first cam 10 and the second cam 11 are adjusted, and in fig. 9b, the second cam 11 is rotated to a retard direction by an angle Ψ, which is referred to as a phase retard angle of the second cam 11. In both fig. 9a and 9b, the valve is about to open but not open, and the fulcrum 22 of the lever 12 is at position 1.

FIG. 10 is a lift operating schematic with extended valve open duration.

As shown in fig. 10a, the lever fulcrum 22 is set at position 1, that is, the valve lift is at zero lift, the first driven pulley 13 contacts the first cam 10 at point B, and the second driven pulley 14 contacts the second cam 11 at point B'.

As shown in fig. 10B, when the first cam 10 rotates clockwise from point B to point C along the ascending operation segment, the second cam 11 correspondingly rotates counterclockwise from point B 'to point I' along the large base circle, wherein: i ' is a point in the large base circle segment B ' -C '. The first driven wheel 13 is pressed by the ascending working section of the first cam 10 to displace downwards, the second driven wheel 14 rolls along the large base circle section of the second cam 11 without radial displacement, the lever fulcrum 22 displaces along with the displacement of the first driven wheel 13, the lever 12 is forced to swing downwards around the center of a sphere, and the valve 20 is forced to open until the lever fulcrum 22 reaches the position 2(L is Max), and the corresponding valve reaches the maximum lift position.

As shown in fig. 10C, when the first cam 10 rotates clockwise from point C to point I along the large base circle segment of the first cam 10, the second cam 11 simultaneously rotates counterclockwise from point I 'to point C' along the large base circle segment correspondingly, wherein: point I is a point in the large base circle segment C-D of the first cam 10. The first driven pulley 13 rolls on the large base circle segment of the first cam 10 without radial displacement, and the second driven pulley 14 rolls on the large base circle segment of the second cam 11 without radial displacement, so that the lever fulcrum 22 is kept at the position 2, the corresponding valve lift is kept at the maximum lift position, and although the valve maximum lift is not changed, the valve opening duration is prolonged.

Further, as shown in fig. 10D, when the first cam 10 rotates clockwise from the point I to the point J along the large base circle segment of the first cam 10, the second cam 11 simultaneously rotates counterclockwise from the point C 'to the point D' along the descending operation segment correspondingly, wherein: the point J is one of the large base circle segments C-D of the first cam 10, and the first driven wheel 13 rolls on the large base circle segment of the first cam 10 without radial displacement; the driven wheel 11 is driven by the valve spring force W to displace upwards, the lever fulcrum 22 displaces along with the displacement of the second driven wheel 14, the pushing force of the valve spring force W forces the lever 12 to swing upwards around the sphere center until the lever fulcrum 22 reaches the position 1, and the valve 20 is forced to close until the position of zero valve lift is reached.

As described above, when the phase delay angle Ψ of the second cam 11 increases, the maximum valve lift remains constant, the valve closing timing is delayed by an angle Ψ, and the corresponding valve opening duration is also extended by an angle Ψ.

With the continuous increase of the adjusting angle psi, the maximum valve lift is kept constant, the valve closing time is continuously delayed, and the valve opening duration is continuously prolonged.

The phase retardation angle Ψ of the second cam 11 of the present embodiment is at most 15 degrees of cam angle.

In order to meet engine performance, it is sometimes necessary to advance or retard the opening of the valve, as shown in fig. 11, which is an example of a retarded opening valve.

As shown in fig. 11, the first cam 10 is retarded backwards by a phase angle α, in contrast to fig. 6a, whereby the opening timing of the valve 20 is retarded by an angle α. If the phase of the second cam 11 is unchanged, the opening time of the valve 20 is delayed by an angle alpha, while the closing time of the valve 20 is unchanged, the opening duration of the valve 20 is shortened by the angle alpha, and the valve lift is reduced.

Likewise, the first cam 10 can also be advanced forward by a phase angle β, whereby the opening timing of the valve 20 is advanced by an angle β. If the phase of the second cam 11 is unchanged, the opening time of the valve 20 is advanced by beta angle, while the closing time of the valve 20 is unchanged, the opening duration of the valve 20 is retarded by beta angle, and the valve lift is reduced.

If the first cam 10 and the second cam 11 perform the adjustment of the advance and/or retard phases at the same time, the valve lift curves required by various internal combustion engines can be obtained, which is not described in detail.

As shown in fig. 12, a valve lift curve in which the second cam 11 is phase-advanced is described. The curve is changed from 101 to 102, 103 and 104 as the advance angle phi is gradually increased, and the valve lift is changed from L₁Reduced to L₂、L₃And L₄The opening duration is T₁Shortened to T₂、T₃And T₄. Because the closing time of the valve is greatly advanced, the Miller cycle of early closing of the internal combustion engine is formed;

as shown in fig. 13, is a valve lift curve in which the phase of the second cam 11 is retarded. As the retardation angle Ψ gradually increases, the curve changes from 105 to 106 and 107, and the valve lift L thereof₁Always kept unchanged, and the opening duration is T₁Elongation to T₂And T₃. Because the closing time of the valve is greatly delayed, a Miller cycle of late closing of the internal combustion engine is formed;

as shown in fig. 14, is a valve lift curve in which the first cam 10 and the second cam 11 are simultaneously advanced or simultaneously retarded. Where the curve 109 is the case where the first cam 10 and the second cam 11 are not advanced or retarded, the curve 110 is the case where the first cam 10 and the second cam 11 are simultaneously advanced, and the curve 111 is the case where the first cam 10 and the second cam 11 are simultaneously retarded, where the valve lift L is₁And valve opening duration T₁Always kept unchanged;

as shown in fig. 15, is a valve lift curve in which the phase of the first cam 10 is retarded. As the retardation angle α of the first cam 10 gradually increases, the curve changes from 112 to 113, 114 and 115, and the valve lift changes from L₅Is reduced to L₆、L₇And L₈The opening duration is T₅Shortened to T₆、T₇And T₈。

In summary, the opening timing of the valve lift can be changed by the first phaser 6 adjusting the rotational phase of the first camshaft 1; the closing time of the valve lift can be changed by adjusting the rotation phase of the second camshaft 2 through the second phase shifter 7; the rotating phase of the first camshaft 1 is adjusted through the first phaser 6, and the rotating phase of the second camshaft 2 is adjusted through the second phaser 7, so that the opening time, the closing time, the lift and/or the valve opening duration of the valve lift can be changed;

observing fig. 6a, 8a and 10a, regardless of how the phases of the first cam 10 and the second cam 11 are adjusted in advance and/or in delay, the valve opening timing is always at the point where the first cam 10 contacts the first driven wheel 13 at point B, which is the end point of the ascending buffer period/the beginning point of the ascending buffer period of the first cam 10, and similarly, observing fig. 6c, 8c and 10c, the valve closing timing is always at the point where the second cam 11 contacts the second driven wheel 14 at point D', which is the end point of the descending buffer period/the beginning point of the descending buffer period of the second cam 11. This state prevents damage to the valve and the valve seat ring due to a large impact force when the valve is opened and closed, and greatly reduces vibration and noise of the device.

As shown in fig. 16, when the first camshaft 1 and the second camshaft 2 are further rotated to align the small base circle segments of the first cam 10 and the second cam 11 with the first driven pulley 13 and the second driven pulley 14, since the stopper 4 is in contact with the outer circle limit point 23 of the positioning ring 16, the swing position of the lever 12 is limited, so that a gap Δ is generated between the first driven pulley 13 and the first cam 10 or between the second driven pulley 14 and the second cam 11, the first driven pulley 13 and the second driven pulley 14 can freely swing around the pin 15, which causes undesirable vibration of the lever 12. In order to eliminate possible vibrations of the lever 12, a return spring 5 is mounted on the cylinder head.

The return spring can be a torsion spring and/or a spiral spring, one end of which is fixedly mounted on the cylinder cover, and the other end of which is overlapped with one end of the lever, so that the driven

wheel

10 or 11 is always kept in contact with the first cam 10 or the second cam 11. Fig. 16 shows that the first driven pulley 13 is always in contact with the first cam 10, so that the free pivoting of the control lever 12 is controlled.

In this embodiment, the first phaser 6 is a hydraulic or electric phaser, and the second phaser 7 is a hydraulic or electric phaser.

Example 2

As shown in fig. 1 to 5 and 17, the embodiment 2 is a simplified valve timing and lift variable device for an internal combustion engine, which includes: the camshaft phaser comprises a first camshaft 1, a second camshaft 2, a phaser 30, at least one lever assembly 3, limiters 4 and return springs 5, wherein the number of the limiters 4 is the same as that of the lever assemblies 3;

as shown in fig. 2, the first camshaft 1 and the second camshaft 2 are rotatably mounted on the cylinder head of the internal combustion engine in parallel but not coaxially, and the first camshaft 1 and the second camshaft 2 are synchronously rotated through gear engagement or sprocket coupling; a phaser 30 is mounted at the rear end of the second camshaft 2, and the phaser 30 can adjust the timing phase of the second camshaft 2;

as shown in fig. 4, the hydraulic tappets 18 are mounted on the cylinder head such that a line formed by the centers 19 of the two hydraulic tappets 18 is parallel to the first camshaft 1 and the second camshaft 2; one end of the rocker arm 17 has a socket which coincides with and is hinged to the spherical centre 19 of the hydraulic tappet 18; the other end of the rocker arm 17 is overlapped with the top 21 of the valve 20; two ends of the pin shaft 15 are respectively inserted in the middle parts of the two rocker arms 17; the rocker arm 17 can swing around a sphere center 19 by an angle θ, and the swing of the rocker arm 17 drives the lever 12 to swing around the sphere center 19 between a position 1 and a position 2, wherein the position 1 corresponds to a valve zero lift position (L ═ 0), namely a valve closing position, and the position 2 corresponds to a valve maximum lift position (L ═ Lmax), namely a valve maximum opening position.

As shown in fig. 5, the lever 12 is sleeved on the pin 15 at a middle pivot 22, and a positioning ring 16 is sleeved between the pin and the pin, so that the lever 12 can swing around the pin 15; a first driven wheel 13 and a second driven wheel 14 are respectively and rotatably arranged at two ends of the lever 12; when the lever 12 is at the position 1, the outer circle of the positioning ring 16 and the stopper 4 are in contact with a limit point 23, and the stopper 4 limits the further swing of the lever 12;

the first cam 1 is in rolling contact with a first driven wheel 13, and the second cam 2 is in rolling contact with a second driven wheel 14; when the first camshaft 1 and the second camshaft 2 rotate, the first cam 10 and the second cam 11 respectively force the first driven wheel 13 and the second driven wheel 14 in contact with the first cam to displace, so that the lever fulcrum 22 connected with the first driven wheel 13 and the second driven wheel 14 is displaced, the displacement of the lever fulcrum 22 causes the lever 12 to swing around the spherical center 19, so that the valve 20 is forced to swing between the position 1 and the position 2, and the opening and the closing of the valve 20 are formed.

The embodiment 2 is characterized in that: the lift of the adjustment valve 20 can be achieved by adjusting the second camshaft 2 with only one phaser 30, while the valve timing can be adjusted also in the small load region of the internal combustion engine.

As shown in fig. 17, in the absence of the first phaser 6, the valve opening timing is the timing at which the first driven wheel 13 is at the rise buffer B point position of the first cam 10. The original profile 24 is modified to a new profile 25 by modifying the profile of the second cam 11 so that the second cam 11 just touches K 'when the first cam 10 touches the first driven wheel 13 at K point, so that the valve opening time is delayed by an angle epsilon compared to the original profile 24, the valve opening time in the vicinity of K' point of the second cam 11 is already a light load region of the internal combustion engine, and the light load region requires not only a reduction in the valve lift but also a delay in the valve opening. By profile correction of the second cam 11, it is obtained that a change in the valve lift can be obtained simultaneously and also a change in the opening phase of the valve timing can be obtained by using only one phaser 30.

The simple valve timing and lift variable device greatly saves the manufacturing cost.

The rest of the adjustment method is the same as that of embodiment 1, and is not described again.

Example 3

As shown in fig. 18, the embodiment is: a second phaser 7 is mounted on the rear end of the second camshaft 2, the second phaser 7 having a sprocket 28, and a sprocket 27 is mounted on the rear end of the exhaust camshaft 26, the sprocket 28 and the sprocket 27 being coupled by a chain 29 to rotate the second camshaft 2 in the same direction and in synchronism with the first camshaft 1.

Except that the driving method is different from that of embodiment 1, the other parts are the same.

Obviously, the valve variable devices described in the above three embodiments can be applied to a single-cylinder, in-line multi-cylinder and V-type internal combustion engine.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments and application fields, and the above-described embodiments are illustrative, instructive, and not restrictive. Those skilled in the art, having the benefit of this disclosure, may effect numerous modifications thereto without departing from the scope of the invention as defined by the appended claims.

Claims

1. A valve timing and lift variable device for an internal combustion engine, comprising: first camshaft, second camshaft, at least one lever subassembly, the stopper and reset spring the same with lever subassembly quantity, first phaser and second phaser, its characterized in that:

2. A valve timing and lift variable device for an internal combustion engine according to claim 1, characterized in that: the profile curves of the two cams jointly determine the lift curve of the valve, wherein: the rising buffer section and the rising working section of the first cam profile curve are used for managing the rising section of the valve lift curve, and the opening time and the valve lift of the valve can be changed by adjusting the rotation phase of the first cam; the descending buffer section and the descending working section of the second cam profile curve are used for managing the descending section of the valve lift curve, and the closing time of the valve and the size of the valve lift can be changed by adjusting the rotation phase of the second cam; by adjusting the rotational phase of the first cam and the second cam simultaneously, the opening time, the closing time, the magnitude of the lift and/or the valve opening duration of the valve can be changed.

3. A valve timing and lift variable device for an internal combustion engine, comprising: the device comprises a first cam shaft, a second cam shaft, a phaser, at least one lever assembly, limiters and return springs, wherein the quantity of the limiters is the same as that of the lever assemblies; the method is characterized in that:

4. A valve timing and lift variable device for an internal combustion engine according to claim 3, characterized in that: the profile curves of the two cams jointly determine a lift curve of the valve, the closing time of the valve, the magnitude of the valve lift and the opening duration of the valve can be changed by adjusting the rotation phase of the second cam through a phaser, and meanwhile, in a small-load area of the internal combustion engine, the opening time of the valve can be delayed by an epsilon angle, and the maximum value of the epsilon angle is not more than 10 degrees of cam rotation angle.

5. A valve timing and lift variable device for an internal combustion engine according to claim 2, characterized in that: the second cam phase is advanced to form a Miller cycle of early closing of the internal combustion engine, and the phase advance angle of the second cam is up to 70 degrees of cam rotation angle; the second cam is retarded in phase to form a miller cycle of late closing of the internal combustion engine, the second cam retardation angle being at most 30 cam degrees.

6. A valve timing and lift variable device for an internal combustion engine according to claim 1, characterized in that: no matter how the lift is changed, the valve is always opened when the end point of the first cam ascending buffering section/the initial point of the ascending working section is contacted with the first driven wheel, and the valve is always closed when the end point of the second cam descending buffering section/the initial point of the descending buffering section is contacted with the second driven wheel, so that the impact force generated when the valve is opened and closed is reduced to the maximum extent.

7. A valve timing and lift variable device for an internal combustion engine according to claim 1, characterized in that: the rear end of the first cam shaft is provided with a first gear, the second phase device is provided with a second gear, and the first gear and the second gear form a gear pair which can enable the first cam shaft and the second cam shaft to synchronously rotate in opposite directions.

8. A valve timing and lift variable device for an internal combustion engine according to claim 3, characterized in that: the first gear is mounted at the rear end of the first camshaft, and the phaser has a second gear, the first gear and the second gear forming a gear pair capable of rotating the first camshaft and the second camshaft in opposite directions in synchronism.

9. A valve timing and lift variable device for an internal combustion engine according to claim 1, characterized in that: the exhaust camshaft is provided with a first chain wheel, the second phase device is provided with a second chain wheel, and the first chain wheel and the second chain wheel are coupled by a chain so that the first camshaft and the second camshaft synchronously rotate in the same direction.

10. A valve timing and lift variable device for an internal combustion engine according to claim 3, characterized in that: the exhaust camshaft is provided with a first chain wheel, the phaser is provided with a second chain wheel, and the first chain wheel and the second chain wheel are coupled by a chain so that the first camshaft and the second camshaft synchronously rotate in the same direction.

11. A valve timing and lift variable device for an internal combustion engine according to claim 1 or 3, characterized in that: the return spring can be a torsion spring and/or a spiral spring, one end of the return spring is fixedly arranged on the cylinder cover, the other end of the return spring is in lap joint with one end of the lever, and the return spring enables the first driven wheel to be always in contact with the first cam or the second driven wheel to be always in contact with the second cam.

12. A valve timing and lift variable device for an internal combustion engine according to claim 1, characterized in that: the first phaser is a hydraulic or electric phaser, and the second phaser is a hydraulic or electric phaser.

13. A valve timing and lift variable device for an internal combustion engine according to any one of claims 1 or 3, characterized in that: the phaser is a hydraulic or electric phaser.

14. A valve timing and lift variable device for an internal combustion engine according to any one of claims 1, 2, 3 or 4, characterized in that: the method can be applied to single-cylinder, in-line multi-cylinder and V-shaped internal combustion engines.