CN101581238B

CN101581238B - Variable valve driving system for internal combustion engine

Info

Publication number: CN101581238B
Application number: CN 200810099528
Authority: CN
Inventors: I·梅瑟利
Original assignee: Mechadyne PLC
Current assignee: Mechadyne PLC
Priority date: 2008-05-13
Filing date: 2008-05-13
Publication date: 2013-07-17
Anticipated expiration: 2028-05-13
Also published as: CN101581238A

Abstract

The invention relates to a variable valve driving system for an internal combustion engine, which allows auxiliary valve action to be used for providing examples of selectively enabling impossible internal exhaust gas to circulate. The variable valve driving system comprises two valves, a first cam and a second cam, wherein the first cam acts on the first valve through a rocking arm which can pivot around a fixed pivotal axis; the second cam is provided with at least two convex parts and acts on the second valve through a second rocking arm which can pivot around an eccentric wheel; the secondconvex part of the two convex parts of the second cam is used for opening the second valve when the first valve is opened by the first cam. A locking mechanism which can be operated selectively locks the eccentric wheel in a fixed position, and each convex part of the second cam in the fixed position enables the second valve to be opened. When the locking mechanism is released, a joint between th e eccentric wheel and the first rocking arm enables the eccentric wheel or allows the eccentric wheel to move in a mode opposite to the lift range of the second valve caused by the second convex part of the second cam when the first valve is opened.

Description

The variable valve driving system that is used for internal-combustion engine

Technical field

The present invention relates to the variable valve driving system for internal-combustion engine.

Background technique

As everyone knows, the changeable air valve transmission improves fuel economy and effulent by hot waste gas being introduced again can be used in the firing chamber.This technology is often referred to as internal exhaust gas recirculation (EGR).It is different from via leading to intake manifold from gas exhaust manifold and comprising the external exhaust gas recirculation that the passage of EGR valve is implemented.

A kind of method that produces internal EGR relates to opens exhaust valve again during intake stroke.When piston moved to the cylinder bottom, exhaust and air inlet were introduced in the cylinder before compression and igniting.

European patent EP 1649148 illustrates the example of continuous variable lift system, and this system will be from the lift addition of the cam profile of two separation, to open exhaust valve again during intake stroke.The amount that the internal EGR that produces when auxiliary exhaust door lift changed continuously is convenient in this system is accurately controlled.

Summary of the invention

The present invention attempts to provide auxiliary valve (event), and it can be chosen as required and make internal EGR become possibility or impossible, and does not have complexity and the cost of continuous variable valve system.

According to the present invention, a kind of variable valve driving system for internal-combustion engine is provided, this system comprises: first air-exchanging valves, first cam, it is by acting on first valve around first rocking arm of fixing pivot axis, second air-exchanging valves, second cam, it has at least two protuberances and by acting on the duaspiracle around second rocking arm that eccentric wheel pivots, second protuberance in two protuberances of described second cam is provided in first valve opens duaspiracle when being opened by first cam, Cao Zuo lockable mechanism optionally, be used for eccentric wheel is pinned in the fixed position, in the fixed position, each protuberance of second cam is opened duaspiracle, and in response to the device of the position of first rocking arm, when lockable mechanism was released, described device was used for moving in the opposite mode of lift of the duaspiracle that causes with second protuberance of second cam at the first valve-opening period chien shih eccentric wheel or allowable offset wheel.

The present invention utilizes a kind of rocker type switch system, but to produce the auxiliary lift of switch in one of them of a pair of valve.Should auxiliary open to have only when unswitched valve and can optionally take place during from its valve seat elevate a turnable ladder.Like this, compare complexity and the cost that can significantly reduce valve system with the continuous variable valve system.

Description of drawings

Further describe the present invention below with reference to the accompanying drawings by way of example, wherein:

Fig. 1 illustrates the sectional view by two valves of same cylinder, and each valve has corresponding operation of cam, cam follower, push rod and actuator rocker arm;

Fig. 2 is the perspective view of valve system that comprises the assembling of parts shown in Figure 1;

Fig. 3 is the sectional view by the valve system of Fig. 2, and section plane is by the axis of pitman arm shaft;

Fig. 4 is the perspective view that is similar to Fig. 2, and optional embodiment of the present invention is shown;

Fig. 5 is the sectional view that is similar to Fig. 3, and this sectional view is by the pitman arm shaft of embodiments of the invention shown in Figure 4;

Fig. 6 is the perspective view of third embodiment of the invention; And

Fig. 7 is that section plane is perpendicular to the pivot axis of this rocking arm by the sectional view of embodiment's shown in Figure 6 first rocking arm.

Embodiment

Fig. 1 comprises two

valves

10 and 22 by two

cams

20 and 36 operations to valve system shown in Figure 3.For the sake of clarity, suppose that first valve 10 is intake valve, and duaspiracle 22 is exhaust valve, although always there is no need this situation.

The cam 20 that is used for intake valve 10 has single protuberance and by cam follower 16, push rod 14 with can act on valve 10 around the rocking arm 12 that pitman arm shaft 18 pivots.This pitman arm shaft 18 is installed in the engine cylinder cap in two

column pieces

38 and 40, makes its axis fix.

Exhaust valve 22 is driven by the cam 36 with two protuberances.One of them protuberance is configured to open exhaust valve 22 during exhaust stroke, and another protuberance is opened exhaust valve 22 to be used for the duaspiracle action during intake stroke.This duaspiracle action allows that again waste gas (EGR) enters the firing chamber again, mixes to fill gas phase with the air inlet that enters by intake valve 10.

Just as will be described below, the power train of exhaust valve is configured to only allow second exhaust valve actuation in two exhaust valve actuation optionally to connect and close, in order to motor can at any time be moved under the situation that has or do not have internal EGR as required.

Cam 36 acts on the flexible cam follower 32, and the inside and outside part of this flexible cam follower 32 is offseted away by spring 34.Push rod 30 passes to one of them arm of rocking arm 24 with the motion of cam follower 32, and its another arm acts on the valve 22.Rocking arm 24 pivots around eccentric wheel 26, and this eccentric wheel itself is around the axis rotation of pitman arm shaft 18.

Except as otherwise noted, above-described power train is applicable to the embodiment that the present invention shown in the accompanying drawing is all.For fear of unnecessary repetition, in whole specification, will keep identical reference character for identical component.But be modified under the situation of said function at component, add 100 for second embodiment at its reference character, and add 200 for the 3rd embodiment at its reference character.

In all three embodiments of the present invention that will describe, motor namely has the pattern of EGR and does not have the pattern of EGR with two kinds of mode operations.In the EGR pattern, eccentric wheel 26 keeps static by lockable mechanism, and this lockable mechanism locks onto eccentric wheel in fixed position shown in Figure 1 contiguous column piece.This causes exhaust valve 22 in each motor operation cycle period unlatching twice, once during exhaust stroke, once during intake stroke.

In non-EGR pattern, eccentric wheel 26 remains on its fixed position for the whole valve lift action of first protuberance of the cam corresponding with the exhaust stroke of motor.But during intake stroke, eccentric wheel 26 turns clockwise or allows its axis around pitman arm shaft 18 to turn clockwise around the axis of pitman arm shaft 18, opens to prevent exhaust valve 22.More particularly, when moving upward under the effect of second nose of cam with push rod 30, eccentric wheel 26 turn clockwise and the raise axis of walking around of rocking arm 24.If the motion at eccentric center is equal to or greater than the maximum lift of second nose of cam, then valve 22 will not opened.

The embodiment's of three descriptions of the present invention part that differs from one another only is to realize the mode with necessity swing of the synchronous eccentric wheel 26 of the operation circulation of motor.When the auxiliary exhaust lift was deactivated, all three illustrated embodiments utilized the motion of intake rocker that eccentric wheel 26 can be rotated.

In the embodiment of Fig. 1 to Fig. 3, hydraulically operated latch pin 50 can axial motion between two terminal positions.In primary importance (shown in Figure 3), eccentric wheel 26 is locked to column piece 40 so that motor can be with the EGR mode operation.In the second place, this latch pin 50 directly is bonded in the hole of rocking arm 12, makes the eccentric wheel 26 of second rocking arm 24 move with first rocking arm 12.Therefore, when moving to open intake valve 10 with rocking arm 12, it clockwise rotates eccentric wheel 26 so that impossible with the EGR event of top describing mode.

During both rotations of second cam 36 and eccentric wheel 26, the gap in the system may change, and during this period, the spring 34 of the clearance adjuster in the cam follower 32 will guarantee that push rod 30 keeps contacting with rocking arm 24.

Eccentric wheel 26 in the embodiment of Fig. 1 to Fig. 3 or be forced to be locked to main shape fast 40 or forcibly driven by rocking arm 12.The embodiment of Fig. 4 to Fig. 7 makes the structure of lockable mechanism be simplified by utilizing following phenomenon, namely, because the resistance of valve 22, not the eccentric wheel of Suo Zhuing since push rod 30 move upward with cam follower 32 in the spring 34 of clearance adjuster self is turned clockwise.Therefore do not need eccentric wheel 26 to drive on all time being forced to property ground.

As shown in Figure 5, the lockable mechanism of second embodiment of the invention comprises the latch pin 150 that is merely able to eccentric wheel 126 is locked to column piece 40.When latch pin 150 withdrawals, eccentric wheel can freely move.But, ridge 160 restrictions that its range of movement is axially stretched out from eccentric wheel 126 and cooperates with chock 162 on the rocking arm 112 of intake valve 10.These two elements form empty moving joint.

Eccentric wheel 126 is left from its locking position elastic biasing by clearance adjuster spring 34.During first exhaust valve actuation, moving upward of push rod 30 applies a power with the eccentric wheel 126 that turns clockwise.But, because intake valve is closed the eccentric rotation of contact preventing between the chock 162 on ridge 160 and the rocking arm 112.In this context, the valve spring of pointing out intake valve 20 should be made sufficiently rigidity, and to rotate eccentric active force with opposing be very important.Therefore eccentric wheel 126 keeps static and exhaust valve 22 can be opened by first nose of cam.

On the other hand, when second protuberance is attempted to open exhaust valve 22, because intake rocker 112 has been turned clockwise to open intake valve 10, this eccentric wheel 126 will be turned clockwise, and driven member 34 will stretch to keep its chock 162 to contact with ridge 160.Therefore eccentric wheel 126 can rotate, and replaces opening exhaust valve 22, and moving upward of push rod absorbed by the gap in the cam follower 32 then.Like this, prevent that the EGR valve event from taking place.

Except the mode that take in the gap in system, the embodiment of Fig. 6 and Fig. 7 is identical with the embodiment of Fig. 4 and Fig. 5 basically.Because eccentric wheel and pitman arm shaft 218 are one, the sky that eccentric wheel is connected in first rocking arm 212 moves joint and comprises more simply from pitman arm shaft 218 and radially stretch into pin 270 the tangential elongated hole 272 of inlet valve rocker 212.And the clearance adjuster on the cam follower also can save and by acting between column piece 240 and the pitman arm shaft 218 that the torsion spring 274 of eccentric wheel towards its locking position biasing replaced.In this case, spring 274 guarantee rocking arm 218 all time all and push rod 30 and valve 22 keep in touch and allow between the end of pin 270 and elongated hole 272, to have the gap.

The embodiment of Fig. 6 and Fig. 7 does not need the clearance adjuster of spring biasing in cam follower, its structure is equally applicable to cammer, and wherein torsion spring 274 can be controlled this intrasystem additional clearance when second lift is deactivated.

Claims

1. valve driving system that is used for internal-combustion engine comprises:

First air-exchanging valves,

First cam, it is by can acting on first air-exchanging valves around first rocking arm of fixing pivot axis,

Second air-exchanging valves,

Second cam, it has at least two protuberances and by acting on second air-exchanging valves around second rocking arm that eccentric wheel pivots, second protuberance in two protuberances of described second cam is provided in and opens second air-exchanging valves when first air-exchanging valves is opened by first cam

Optionally Cao Zuo lockable mechanism is used for eccentric wheel is pinned in the fixed position, and in the fixed position, each protuberance of second cam is opened second air-exchanging valves, and

Device in response to the position of first rocking arm, when lockable mechanism was released, described device was used at the first air-exchanging valves open period eccentric wheel or allowable offset wheel being moved in the opposite mode of lift of second air-exchanging valves that causes with second protuberance of second cam.

2. valve driving system as claimed in claim 1, wherein, described lockable mechanism has primary importance and the second place, and in primary importance, described eccentric wheel is prevented from motion, and in the second place, described eccentric wheel directly connects to move with first rocking arm.

3. valve driving system as claimed in claim 2, wherein, the clearance adjuster of spring biasing is arranged in the cam follower of second cam, in order to absorb any variation in the gap between second cam and second rocking arm.

4. valve driving system as claimed in claim 1, wherein, described lockable mechanism has primary importance and the second place, in primary importance, described eccentric wheel is prevented from motion, in the second place, described eccentric wheel freely moves, and the joint that wherein acts between eccentric wheel and first rocking arm limits eccentric motion according to the position of first rocking arm in the mode opposite with the lift of second air-exchanging valves.

5. valve driving system as claimed in claim 4, wherein, described joint comprises the chock that is positioned on first rocking arm.

6. valve driving system as claimed in claim 5, wherein, described eccentric wheel is promoted to leave described fixed position to contact the chock on first rocking arm by the effect of spring.

7. valve driving system as claimed in claim 6, wherein, this spring is included in the driven member of second cam and is used for the complemental air door transmission system because described eccentric kinetic gap changes.

8. as claim 4 or 5 described valve driving systems, wherein, torsion spring is set so that described eccentric wheel is setovered towards described fixed position.

9. according to the described valve driving system of one of claim 1-5, wherein, described lockable mechanism is hydraulically operated.