CN102102559B

CN102102559B - Compression releasing engine braking method and device

Info

Publication number: CN102102559B
Application number: CN201110057912.9A
Authority: CN
Inventors: 杨洲
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-03-10
Filing date: 2011-03-10
Publication date: 2014-09-24
Anticipated expiration: 2031-03-10
Also published as: CN102102559A; WO2012119282A1

Abstract

The invention discloses a compression releasing engine braking method and device. A primary piston hole and a secondary piston hole connected with a hydraulic passage are formed in a valve bridge, and a primary piston and a secondary piston in the piston holes are driven by using a braking lug boss of a cam to open an exhaust valve for braking. During braking, the retraction position of the primary piston is kept by using the equal altitude section of the braking cam at the maximum braking lift, the hydraulic passage between the primary piston hole and the secondary piston hole is closed, and the braking load on the secondary piston is transferred to a braking bracket positioned on the valve bridge and is not returned to the primary piston. The primary piston is further driven by using an integrated exhaust lug boss on the cam, the primary piston drives the valve bridge to move and is separated from the braking bracket, and an oil discharge passage in the valve bridge is opened to discharge oil, so that the secondary piston returns to the retraction position, and the braking exhaust door is moved to a closed position. A compression releasing braking mechanism is integrated with a traditional air valve driving chain, and the braking bracket bears the braking load and the weight braking valve lift, so the braking load is reduced and the braking power is increased.

Description

A kind of compression releasing engine braking and device

Technical field:

The present invention relates to mechanical field, relate in particular to the valve actuation field of vehicle motor, particularly a kind of compression releasing engine braking and device.

Background technique:

Engine braking can be divided into compression-release braking and the type braking of losing heart.The compression-release braking of motor is opened exhaust valve in the later stage of engine piston compression stroke, in the early stage of expansion stroke (generally before the normal unlatching of exhaust valve), closes exhaust valve.A precedent of compression-release break is disclosed at U.S. Patent number 3220392 in nineteen sixty-five by comings (Cummins).Braking system is delivered to by machinery input the exhaust valve that will open through oil hydraulic circuit.On oil hydraulic circuit, be usually included in reciprocating main piston in master piston bore, this to-and-fro motion comes from the machinery input of motor, such as the motion of motor injection cam or the motion of adjacent exhaust cam.The hydraulic fluid that moves through of main piston is delivered to the sub-piston on oil hydraulic circuit, makes its to-and-fro motion in slave piston bore, and sub-piston acts on exhaust valve directly or indirectly, produces the valve motion of engine braking running.

The disappointing type braking of motor is that exhaust valve is except normal unlatching, also in partial periodicity, keep perseverance in a small amount to open (partial periodicity loses heart and brakes), or within the cycle of non-exhaust stroke (aspirating stroke, compression stroke, and expansion stroke) keep perseverance in a small amount to open (disappointing braking of complete period).Partial periodicity loses heart and brakes and the disappointing main distinction of braking of complete period, is that the former does not open exhaust valve in most aspirating stroke.The inventor provides relevant explanation and example at U.S. Patent number 6594996 for air-leakage type engine brake system and method.

The difference of the compression-release braking of motor and the type braking of losing heart mainly contains 2 points.First main distinction is open phase (period of braking) difference of braking exhaust valve.The complete period braking exhaust valve of disappointing type braking is opened all the time, does not therefore involve the opening time.The opening time of the braking exhaust valve of the disappointing type braking of partial periodicity is the later stage in the aspirating stroke of motor; And the opening time of the braking exhaust valve of compression-release braking is in the later stage of the compression stroke of motor, late more a lot of than the opening time of the braking exhaust valve of the disappointing type braking of partial periodicity, the load of therefore opening is also much bigger.Second main distinction is Lift (brake valve liter) difference of braking exhaust valve.The brake valve liter of the braking exhaust valve of the type that loses heart braking is roughly 0.5～1.0mm (being generally less than 1.0mm), and the brake valve liter of the braking exhaust valve of compression-release braking is roughly 2.0～3.5mm (brake valve of hydraulic brake rises and is generally greater than 2.0mm).Above-mentioned difference causes the difference of designing requirement and braking ability.The braking force of compression-release is greater than the type braking of losing heart, but the braking unlatching load of the type braking of losing heart is braked much smaller than compression-release.The type break that loses heart must be combined use with exhaust brake (as exhaust butterfly valve), and compression-release break can use separately (not needing exhaust brake).

A precedent of disappointing braking system of motor complete period is disclosed for No. 3525317 at U. S. Patent in 1970 by Miao Er (Muir).This braking system is divided into third gear by engine braking.First grade is the frictional loss that causes of motor and each moving element of vehicle and the braking that produces.Second gear is disappointing braking of complete period that continuous permanent the opening in a small amount of the exhaust valve maintenance of motor produced.Third gear is to increase exhaust butterfly valve on losing heart the basis of braking in the complete period of second gear, produces Associated brake.

The Ku Bishi (Kubis) of Germany graceful (MAN) equals at U. S. Patent, to disclose disappointing braking system of engine section cycle for No. 5086738 in 1992.During engine braking, exhaust valve is opened in a small amount when engine charge stroke finishes soon, then in whole compression stroke, keeps perseverance in a small amount to open, and close the early stage of the last expansion stroke at motor.

Before said, the motor independent using effect of type break of losing heart is bad, braking force is far below compression-release break.Therefore, the disappointing type break of motor is all combined use with engine exhaust and brake device (as exhaust butterfly valve), forms Associated brake.Use exhaust butterfly valve or other exhaust current-limiting apparatus that exhaust back pressure is raise and likely cause exhaust valve knock-on or float (float valve).Engine Industry is generally to float valve disapprove, because the opening and closing of exhaust valve are not by cam-actuated during float valve, the seating velocity of valve is uncontrollable.Too large valve crash speed is likely damaged motor.Yet Canadian PacBrake disclosed for No. 4848289 and has used exhaust brake to improve the braking method that exhaust back pressure causes float valve at U. S. Patent in 1989.

The Volvo of Sweden (Volvo) discloses a kind of Associated brake method that compression-release engine brake with exhaust brake together with used No. 5146890 in 1992 at U. S. Patent.Wherein the brake cam of motor, except compression releasing brake boss, has increased exhaust gas recirculatioon (EGR) boss.Exhaust valve was opened in the later stage of aspirating stroke, and the high back pressure tail gas being produced by exhaust brake (being air during braking), from the anti-engine cylinder that fills in outlet pipe, increases compression brake power.

The La Mo (Rammer) of Germany graceful (MAN) equals at U. S. Patent, to disclose a kind of exhaust brake that utilizes for No. 5692469 in 1997 and improves the apparatus and method that exhaust back pressure causes float valve (valve knock-on) and then opens the type break that loses heart.When exhaust back pressure is enough high, exhaust valve is floating when aspirating stroke is closed on end to be left or bounces.At this exhaust valve between the float period, with a braking device, it is intervened, namely before floating exhaust valve closing of opening, the piston of controlling by individual oil pressure is stopped, stop it to close, allow it keep perseverance in a small amount to open, disappointing braking of generating portion cycle (exhaust valve cuts out after exhaust stroke).This braking system is the motor for the single valve of every cylinder.2006, La Mo (Rammer) etc. are the motor (No. 7013867th, U. S. Patent, No. 200310123153.7th, Chinese patent) to the double valve of every cylinder by above-mentioned technological expansion.

Reliability and the durability of the above-mentioned air-leakage type engine braking system of Germany graceful (MAN) are faced with a lot of problems, because it depends on the intermittence of braking exhaust valve, open or float, and this is all inconsistent in time and size.As everyone knows, the flying height of exhaust valve depends on exhaust back pressure, and exhaust back pressure depends on the rotating speed of motor, and is subject to the quality of exhaust brake and the impact of control and vent systems design.In motor, slow-speed of revolution when speed, the unsteady of exhaust valve may not have not or at all, engine braking apparatus cannot start.And now the demand of engine braking is very high because the commercial vehicle engine most of the time operate in, the slow-speed of revolution.In addition the exhaust valve that too high exhaust back pressure not only floats and is braked, the exhaust valve that also floats and do not brake simultaneously.The seating velocity of the exhaust valve of not braking will be too large, affect reliability and the durability of motor.

The inventor discloses the disappointing type braking device of a kind of partial periodicity that utilizes actuated by cams and produce and method in 2010 at U. S. Patent No. 7673600 (Chinese patent application publication number CN1991136A).In the valve bridge of motor, be integrated with major and minor piston.In main piston, there is unidirectional delivery valve, in the hydraulic pressure runner between main piston and sub-piston, be also provided with another one braking one-way valve.The conventional exhaust cam of brake cam and motor is integrated, comprises the type braking boss that loses heart.The type that loses heart braking boss started from the interior basic circle of cam toward rising in the later stage of engine charge stroke.Near the lower dead center of aspirating stroke, rise to top lift, then during the compression stroke of motor and expansion stroke, keep this top lift constant, finally transition enters conventional exhaust boss smoothly.During engine braking, not to raise unsteady exhaust valve and open braking by exhaust back pressure, but promote the main piston in valve bridge by braking boss, main piston drives sub-piston to open exhaust valve, sub-piston is locked in extended position by braking one-way valve, keep perseverance in a small amount to open exhaust valve, the disappointing type braking of generating portion cycle.

The braking drive organ of above-mentioned many braking device is to be all integrated in the valve bridge of motor.A precedent of valve bridge braking device be by Calvi (Calvin) in 1970 at U.S. Patent number 3,520,287 disclose.Whole valve bridge is enclosed within on a central guide rod.There are braking oil duct and control valve in guide rod inside.Guide rod top is as a brake piston, and valve bridge slides along brake piston by its inner piston hole.

Valve bridge arrestment mechanism having improved by this cola (Sickler) in 1986 at U.S. Patent number 4,572,114 disclose.A special-purpose brake piston is placed in the piston hole of opening on valve bridge mediad, and the relative movement between brake piston and valve bridge is reduced greatly.This valve bridge arrestment mechanism, for four stroke engine, compresses releasing brake twice but produce in each cycle period.

U.S. Jie Kebo company (JVS) is that the valve bridge braking device (referring to U.S. Patent Publication No. US 20050211206, one of inventor that the inventor is this patent application) of modern (Hyundai) truck company of Korea S Design and manufacture has increased a kind of valve and rises reset mechanism on the basis of the valve bridge arrestment mechanism of this cola (Sickler).In addition, one to three piston can be set in valve bridge, during braking, open one or two exhaust valve.

Yellow (Huang) and the inventor and Shu Woer (Schwoerer) disclose a kind of method of utilizing brake cam molded line to realize Brake Design requirement and optimization braking function in 2007 at U. S. Patent No. 7284533 (Chinese patent application publication number CN101490393A).

Summary of the invention:

The object of the present invention is to provide a kind of compression releasing engine braking, described this compression releasing engine braking will solve the reliability that in prior art, engine braking mechanism exists and durability is bad, installment and debugging is inconvenient and the technical problem of increase motor height and weight.

This compression releasing engine braking of the present invention comprises a process of utilizing the exhaust valve chain unlatching exhaust valve of motor, described exhaust valve chain comprises cam, rocking arm and valve bridge, in the exhaust valve of described motor, include a first row valve and a second row valve, in described cam, contain at least one braking boss, described braking boss comprises that an interior basic circle from cam rises to the ascent stage of maximum lift and contour section of the maximum lift described in a maintenance, in described rocking arm, be provided with an oil supply gallery, wherein, mediad upper shed at described valve bridge arranges a master piston bore, one end at valve bridge arranges a slave piston bore under shed, between described master piston bore and slave piston bore, connect a hydraulic channel is set, master piston bore inner sliding type a main piston is set, main piston has an extended position and a retracted position with respect to master piston bore, slave piston bore inner sliding type a sub-piston is set, the upper end of main piston is connected with described rocking arm, an oil circuit is set in main piston, the upper end of described oil circuit is communicated with the oil supply gallery in described rocking arm, the lower end of oil circuit is communicated with master piston bore, between master piston bore and oil supply gallery, or a unidirectional delivery valve is set within oil supply gallery, the fuel feeding direction of described unidirectional delivery valve is from oil supply gallery to master piston bore, the lower end of sub-piston is connected with described first row valve, the downside of the valve bridge the other end is connected with described second row valve, upside in the valve bridge one end at slave piston bore place arranges a brake holder, at the described exhaust valve chain that utilizes motor, open in the process of exhaust valve, first, by described oil supply gallery and unidirectional delivery valve to master piston bore fuel feeding, main piston is placed in to extended position, open the hydraulic channel between master piston bore and slave piston bore, then, utilize the ascent stage of braking boss in cam to drive described rocking arm, make rocking arm promote main piston and shift to retracted position from extended position, utilize described brake holder to stop on valve bridge moves simultaneously, utilize the hydraulic pressure in described hydraulic channel that the motion of main piston is passed to sub-piston, force described sub-piston to stretch out in slave piston bore downwards, open first row valve, afterwards, utilize contour section of driving rocking arm braking boss in cam, main piston is remained on retracted position in master piston bore, blocking-up master piston bore is by described hydraulic channel and the hydraulic pressure transfer between slave piston bore, sub-piston is remained on to the extended position in slave piston bore, the open mode that keeps first row valve, utilize the brake load on brake holder carrying sub-piston simultaneously.

Further, in the valve bridge one end at slave piston bore place, at least one emptying passage is set, the lower end of described emptying passage is communicated with slave piston bore, utilize the upper end open of the lower end closed emptying passage of described brake holder.

Further, a descending branch is set on described braking boss, the starting point of described descending branch is connected to the described end of contour section, the terminal of descending branch is got back to or near the interior basic circle of cam.

Further, in cam, brake boss after contour section, enter in the process of descending branch, utilize rocking arm to do reversing motion, make main piston shift to extended position from retracted position, open the opening of hydraulic channel in master piston bore, connect the hydraulic pressure transfer between master piston bore and slave piston bore, sub-piston is moved to retracted position under the active force of first row valve.

Further, the axial setting by the oil circuit in main piston along main piston, is arranged on the lower ending opening of oil circuit in the lower end surface of main piston.

Or, integrated form exhaust boss is set on described cam, a slow section that rises is set on described braking boss, the described slow starting point that rises section is connected to the described end of contour section, the slow terminal that rises section is imported to described integrated form exhaust boss, in cam, brake boss after contour section, enter in the process of slow liter section, utilize the slow section that rises of braking boss to drive described rocking arm, make rocking arm inside contract back locational main piston and down promote valve bridge by being positioned at master piston bore, make the valve bridge one end at slave piston bore place separated with the described brake holder that is located thereon side, open the upper end open emptying of emptying passage, reduce the hydraulic pressure in slave piston bore, make sub-piston under the active force of first row valve in slave piston bore migration retracted position upwards, make the first row valve migration closed position that makes progress.

Further, the process of the described exhaust valve chain unlatching exhaust valve that utilizes motor comprises the following steps:

1) open the brake control mechanism of motor, by described oil supply gallery and unidirectional delivery valve to the master piston bore fuel feeding in valve bridge,

2) main piston is built in extended position in master piston bore, opens master piston bore in valve bridge and the hydraulic channel between slave piston bore,

3) sub-piston is built in retracted position in slave piston bore, and the first row valve below sub-piston is in the closed position,

4) the braking boss of cam moves up from interior basic circle, drives the downward retracted position motion in the master piston bore of valve bridge of main piston in master piston bore,

5) be positioned at that brake holder above the valve bridge of slave piston bore top stops or limiting valve bridge moves upward,

6) moving downward by hydraulic channel of main piston passes to sub-piston, and the sub-piston in the slave piston bore of valve bridge toward extended position motion, is opened first row valve downwards,

7) the braking boss of cam arrives at top lift and continues the described top lift position of maintenance,

8) main piston arrives at retracted position downwards in the master piston bore of valve bridge, closes the hydraulic channel between master piston bore and slave piston bore, stops the hydraulic load on sub-piston to be delivered to main piston,

9) sub-piston arrives at extended position downwards in the slave piston bore of valve bridge, and the first row valve below sub-piston is stayed open in the highest brake valve raise-position and put,

10) utilize the brake holder of valve bridge one end upside at slave piston bore place to support the load that first row valve is passed to sub-piston,

11) the braking boss of cam rolls back interior basic circle from top lift,

12) main piston is up moved back into extended position from the retracted position in the master piston bore of valve bridge, opens the hydraulic channel between master piston bore and slave piston bore,

13) sub-piston is up moved back into retracted position from the extended position in slave piston bore,

14) first row valve is put and is up shifted to closed position from the highest brake valve raise-position.

Further, the process of the described exhaust valve chain unlatching exhaust valve that utilizes motor is further comprising the steps of:

1) brake control mechanism killing engine, stops to the master piston bore fuel feeding in valve bridge,

2) main piston in the master piston bore of cam-driven valve bridge moves downward,

3) main piston actuating valve bridge moves downward, and the valve bridge one end at slave piston bore place is separated with the brake holder of its upside,

4) the emptying passage emptying of open auxiliary piston hole top,

5) sub-piston moves on to retracted position in the slave piston bore of valve bridge.

Further, when main piston slides to extended position from retracted position in master piston bore, utilize main piston to open hydraulic channel and be positioned at the opening in master piston bore, when main piston slides to retracted position from extended position in master piston bore, utilize main piston to close hydraulic channel and be positioned at the opening in master piston bore.

Further, described emptying channel setting has an outlet, and when valve bridge is moved down by actuated by cams, valve bridge is separated with brake holder, opens the outlet of described emptying passage.

Further, described brake holder is fixed on motor, described brake holder comprises link, and described link is positioned at the top of valve bridge.

Further, described brake holder is integrated on described rocking arm, described brake holder comprises link, and described link is positioned at the top of valve bridge.

Further, in described braking boss, include a compression and discharge boss, described compression discharges boss and starts to rise from the interior basic circle of cam in the later stage of the compression stroke of motor, and reach extreme higher position at the near of motor, under the early stage of the expansion stroke of motor, roll back the interior basic circle of cam.

Further, in described braking boss, include a compression and discharge boss and an exhaust gas recirculatioon boss, described compression discharges boss and starts to rise from the interior basic circle of cam in the later stage of the compression stroke of motor, and reach extreme higher position at the near of motor, under the early stage of the expansion stroke of motor, roll back the interior basic circle of cam, described exhaust gas recirculatioon boss started to rise from the interior basic circle of cam in later stage of the aspirating stroke of motor, rolled back the interior basic circle of cam under the early stage of the compression stroke of motor.

Further, an integrated form exhaust boss is set on described cam, in described braking boss, include a compression and discharge boss, described compression discharges boss and starts to rise from the interior basic circle of cam in the later stage of the compression stroke of motor, and rose to extreme higher position before the compression stroke top dead center of motor, in the remaining period of compression stroke of motor and the initial stage of the expansion stroke of motor, keep described extreme higher position, under the remaining period of the expansion stroke of motor, roll back the interior basic circle of cam or import integrated form exhaust boss, described integrated form exhaust boss is comprised of bottom and top, the bottom of integrated form exhaust boss approaches with high with braking boss, the top of integrated form exhaust boss approaches identical with the conventional boss of motor.

Further, in described braking boss, include an exhaust gas recirculatioon boss, described exhaust gas recirculatioon boss started to rise from the interior basic circle of cam in later stage of the aspirating stroke of motor, rolled back the interior basic circle of cam under the early stage of the compression stroke of motor.

Further, an integrated form exhaust boss is set on described cam, in described braking boss, include a compression and discharge boss, described compression discharges boss and starts to rise from the interior basic circle of cam in the latter half of the compression stroke of motor, and rose to extreme higher position before the compression top center of motor, in the remaining period of compression stroke of motor and the early stage of the expansion stroke of motor, keep described extreme higher position, in the remaining period of the expansion stroke of motor, rise and import integrated form exhaust boss.

Further, utilize a preloading spring in exhaust valve chain inside, to keep, by the retracted position of main piston and the exhaust valve chain brake clearance of extended position generation, utilizing not following and impacting of described exhaust valve chain brake clearance elimination exhaust valve chain inside.

The present invention also provides a kind of compression-release engine braking device, described this compression-release engine braking device comprises brake control mechanism and braking drive organ, wherein, described brake control mechanism comprises a control valve being connected with hydraulic pressure generation device, braking drive organ comprises braking casing, oil feeding mechanism, emptying mechanism and brake cam, in described braking casing, be provided with master piston bore and slave piston bore, between described master piston bore and slave piston bore, be provided with the hydraulic channel of a connection, be provided with main piston master piston bore inner sliding type, be provided with sub-piston slave piston bore inner sliding type, described oil feeding mechanism comprises oil supply gallery and unidirectional delivery valve, control valve in described brake control mechanism is connected with the entrance of described oil supply gallery, the outlet of oil supply gallery is connected with master piston bore, described unidirectional delivery valve is arranged between oil supply gallery or oil supply gallery and master piston bore, the fuel feeding direction of unidirectional delivery valve is to enter master piston bore from oil supply gallery, described emptying mechanism comprises Yi Ge oil drain valve, described oil drain valve is communicated with slave piston bore, in described brake cam, contain at least one braking boss.

Further, described braking casing consists of valve bridge, described master piston bore is arranged in a upward opening of described valve bridge central authorities, described slave piston bore is arranged on of one end of valve bridge under shed, described hydraulic channel is arranged in valve bridge and is communicated with master piston bore and slave piston bore, described main piston is arranged in master piston bore, described sub-piston is arranged in slave piston bore, the upper end of main piston is fixedly connected with the rocking arm of motor, in described rocking arm, be provided with an oil supply gallery, in main piston, be provided with an oil circuit, the upper end of described oil circuit communicates with the oil supply gallery in described rocking arm, the lower end of oil circuit communicates with master piston bore, described unidirectional delivery valve is arranged between master piston bore and oil supply gallery or within oil supply gallery, the fuel feeding direction of described unidirectional delivery valve is from oil supply gallery to master piston bore, the upside of the valve bridge one end at slave piston bore place is provided with a brake holder, the valve bridge one end at slave piston bore place is provided with at least one emptying passage, one end of described emptying passage communicates with slave piston bore, the other end of emptying passage is by the lower end closed of brake holder, on described brake cam, be provided with integrated form exhaust boss.

Further, the lower end of sub-piston is connected with a first row valve in engine exhaust port, and the downside of the valve bridge the other end is connected with a second row valve in engine exhaust port.

Further, described brake holder is fixed on motor, and described brake holder comprises link, and described link is positioned at the top of valve bridge.

Further, described brake holder is integrated on rocking arm, and described brake holder comprises link, and described link is positioned at the top of valve bridge.

Further, the link of described brake holder comprises transition piston, and described transition piston is placed in the transition piston hole of valve bridge slidably, and described transition piston hole is positioned on described slave piston bore.

Further, in described braking boss, include a compression and discharge boss, described compression discharges boss and starts to rise from the interior basic circle of cam in the later stage of the compression stroke of motor, and reach extreme higher position at the near of motor, under the early stage of the expansion stroke of motor, roll back or near the interior basic circle of cam.

Further, in described braking boss, include a compression and discharge boss and an exhaust gas recirculatioon boss, described compression discharges boss and starts to rise from the interior basic circle of cam in the later stage of the compression stroke of motor, and reach extreme higher position at the near of motor, under the early stage of the expansion stroke of motor, roll back or near the interior basic circle of cam, described exhaust gas recirculatioon boss started to rise from the interior basic circle of cam in later stage of the aspirating stroke of motor, rolled back the interior basic circle of cam under the early stage of the compression stroke of motor.

Further, on described cam, be provided with an integrated form exhaust boss, in described braking boss, include a compression and discharge boss, described compression discharges boss and starts to rise from the interior basic circle of cam in the later stage of the compression stroke of motor, and rose to extreme higher position before the compression stroke top dead center of motor, in the remaining period of compression stroke of motor and the initial stage of the expansion stroke of motor, keep described extreme higher position, under the remaining period of the expansion stroke of motor, roll back the interior basic circle of cam or import integrated form exhaust boss, described integrated form exhaust boss is comprised of bottom and top, the bottom of integrated form exhaust boss approaches with high with braking boss, the top of integrated form exhaust boss approaches identical with the conventional boss of motor.

Further, on described cam, be provided with an integrated form exhaust boss, in described braking boss, include a compression and discharge boss, described compression discharges boss and starts to rise from the interior basic circle of cam in the latter half of the compression stroke of motor, and rose to extreme higher position before the compression top center of motor, in the remaining period of compression stroke of motor and the early stage of the expansion stroke of motor, keep described extreme higher position, in the remaining period of the expansion stroke of motor, rise and import integrated form exhaust boss.

Further, in described braking drive organ, be provided with a preloading spring.

Further, one end of described preloading spring is placed on described motor, and one end of preloading spring acts on one end of described rocking arm.

Further, in described braking drive organ, be provided with an automatic backlash compensation mechanism.

Working principle of the present invention is: when needs engine braking, brake control mechanism is opened, to braking drive organ fuel feeding.Low-pressure oil (engine lubricating oil) enters in master piston bore from oil supply gallery and unidirectional delivery valve, and main piston in extended position, is opened the hydraulic channel between master piston bore and slave piston bore in the master piston bore of valve bridge.The braking boss of cam is from interior basic circle toward rising, and the main piston in rocking arm actuating valve bridge is down shifted to the retracted position of master piston bore bottom surface from extended position, and moving downward by hydraulic channel of main piston passes to sub-piston.Be positioned at the brake holder above the valve bridge of slave piston bore top, stop valve bridge to rise because of the oil pressure in slave piston bore.Sub-piston in the slave piston bore of valve bridge stretches out downwards, opens the braking exhaust valve being positioned at below sub-piston.Cam enters the top lift of braking boss, and the retracted position at the bottom of main piston arrives at hole downwards in the master piston bore of valve bridge is blocked the entrance of hydraulic channel, closes the hydraulic channel between master piston bore and slave piston bore.Sub-piston arrives at extended position downwards in the slave piston bore of valve bridge, and the exhaust valve below sub-piston is stayed open to a gap.Brake load on sub-piston cannot pass to main piston by hydraulic channel, can only pass to the brake holder being positioned at above the valve bridge of slave piston bore top by valve bridge.Now, main piston and exhaust valve actuator (comprising rocking arm and cam etc.) do not bear brake load.When cam declines from braking the top lift of boss, main piston is up shifted to extended position from the retracted position in the master piston bore of valve bridge, open the hydraulic channel between master piston bore and slave piston bore, the sub-piston in slave piston bore is along with main piston moves up together.Main piston in the master piston bore of valve bridge on get back to extended position, sub-piston in the slave piston bore of valve bridge on get back to retracted position, the exhaust valve below sub-piston is up shifted to closed position.

The integrated form exhaust boss of cam is from interior basic circle toward rising, and the main piston in rocking arm actuating valve bridge is down shifted to the contracting co-located of master piston bore bottom surface from extended position, and moving downward by hydraulic channel of main piston passes to sub-piston.Be positioned at the brake holder above the valve bridge of slave piston bore top, stop valve bridge to rise because of the oil pressure in slave piston bore.Sub-piston in the slave piston bore of valve bridge stretches out downwards, opens the braking exhaust valve being positioned at below sub-piston.Cam enters the top of integrated form exhaust boss, and at the bottom of main piston compressing master piston bore, actuating valve bridge moves downward.Valve bridge is separated with the brake holder that is located thereon face, opens the emptying passage emptying of slave piston bore top in valve bridge, and sub-piston moves on to retracted position from extended position in the slave piston bore of valve bridge.Valve bridge passes to two exhaust valves by the motion at integrated form exhaust boss top, produces conventional exhaust valve motion.

The present invention compares with prior art, and its effect is actively with obvious.It is inner that the present invention is integrated in the existing valve actuation chain of motor by compression-release arrestment mechanism, and utilize brake holder to bear brake load and replacement brake valve liter, simplicity of design, compact structure, reduced the brake load of motor, increase the braking force of motor, improved reliability and the durability of engine operation.

Accompanying drawing explanation:

Fig. 1 is first embodiment cam schematic diagram in interior basic circle position when braking of the compression-release engine braking device in the present invention.

Fig. 2 is the schematic diagram of first embodiment cam extreme higher position in braking boss when braking of the compression-release engine braking device in the present invention.

Fig. 3 is the brake control mechanism of the compression-release engine braking device in the present invention schematic diagram in " opening " position.

Fig. 4 is the schematic diagram of the brake control mechanism of the compression-release engine braking device in the present invention in off-position.

Fig. 5 is the schematic diagram of a kind of cam profile of the compression-release engine braking device in the present invention.

Fig. 6 is a kind of exhaust valve lift curve of the compression-release engine braking device in the present invention and the schematic diagram of intake valve lifting curve.

Fig. 7 is the schematic diagram of another cam profile of the compression-release engine braking device in the present invention.

Fig. 8 is the schematic diagram of another cam profile of the compression-release engine braking device in the present invention.

Fig. 9 is second embodiment cam schematic diagram in interior basic circle position when non-braking of the compression-release engine braking device in the present invention.

Figure 10 is second embodiment cam schematic diagram in interior basic circle position when braking of the compression-release engine braking device in the present invention.

Embodiment:

Embodiment 1:

As depicted in figs. 1 and 2, first embodiment of compression-release engine braking device of the present invention when braking cam 230 respectively in interior basic circle 225 positions and braking boss top lift position.Fig. 1 and Fig. 2 comprise three chief components: exhaust valve actuator 200, exhaust valve 300 (comprising first row valve 3001 and second row valve 3002) and engine braking driving mechanism 100.

Exhaust valve actuator 200 comprises cam 230, cam follower wheel 235, rocking arm 210 and valve bridge 400.Exhaust valve actuator 200 and exhaust valve 300 are combined and can be described as exhaust valve chain.Conventionally in one end of rocking arm 210 (near a side of valve bridge 400 or near a side of cam 230) with valve clearance regulating system.Valve clearance regulating system in the present embodiment consists of the valve clearance adjusting screw 110 that is arranged on valve bridge 400 1 sides, and valve clearance adjusting screw 110 is positioned on rocking arm 210 and by lock nut 105 fixes.Valve clearance adjusting screw 110 with resemble foot pad 114 and be connected.Be arranged on pitman arm shaft 205 rocking arm 210 swing types.

First row valve 3001 and second row valve 3002 by valve spring 3101 and valve spring 3102 (the being called for short valve spring 310) valve seat 320 of overhead in engine cylinder-body 500, stop gas (being air during engine braking) flowing between engine cylinder and outlet pipe 600 respectively.Exhaust valve actuator 200, by the mechanical motion of cam 230, passes to first row valve 3001 and second row valve 3002 by valve bridge 400, and it is is periodically opened and closed.

Braking drive organ 100 comprises braking casing, brake holder and brake cam.Braking casing in the present embodiment adopts the valve bridge 400 of motor.The mediad upper shed of valve bridge 400 is provided with a master piston bore 415, and one end of valve bridge 400 is provided with a slave piston bore 190 under shed.Master piston bore 415 is connected by a hydraulic channel 412 with slave piston bore 190.Master piston bore 415 is also connected with the oil supply gallery 115 of its top by unidirectional delivery valve 172.In master piston bore 415 and interior main piston 162 and the sub-piston (being again brake piston) 160 that be provided with slidably respectively of slave piston bore 190.Above main piston 162, be subject to the effect from rocking arm 210.Being connected with the first row valve 3001 of being used as to brake of motor below of sub-piston 160.Being connected with the second row valve 3002 of the non-braking action of motor below of the other end of valve bridge 400.In the valve bridge 400 of slave piston bore 190 tops, be provided with emptying passage 197, emptying passage 197 and slave piston bore 190 communicate, and the top of emptying passage 197 is provided with a brake holder 125.Brake holder 125 comprises adjustable link 1052 and 1142 and fastening piece 1102.Brake holder 125 can be fixed on motor.Brake holder 125 (passing through link) is positioned on the valve bridge 400 of slave piston bore 190 tops and the outlet of sealing emptying passage 197.The conventional cam of brake cam and motor is integrated, contains at least one braking boss and integrated form exhaust boss 220 on integrated cam 230.The compression that the braking boss of the cam 230 is here included on basic circle 225 discharges boss 233 and exhaust gas recirculatioon boss 232.

A preloading spring 198 can be set between exhaust rocker arm 210 and motor.In the present embodiment, preloading spring 198 is flat spring, and its one end is placed in brake holder 125, and the other end is placed on rocking arm 210.Preloading spring 198 can be the spring of helical spring and other form.

Preloading spring 198 also can be used different mounting types, is arranged on different places, such as between main piston 162 and valve bridge 400, between cam 230 (or push rod of push rod engine) and rocking arm 210 etc.Preloading spring 198 keeps by the retracted position (Fig. 2) of main piston 162 and extended position (Fig. 1) at the inner brake clearance 234 generating of exhaust valve chain (this gap during in non-braking can interior basic circle 225 and cam follower wheel 235 at cam 230 between), not the following and impact of elimination exhaust valve chain inside.

At the interior locating stud 137 that arranges of valve bridge 400, restraining groove 142 is set on sub-piston 160, form piston limit mechanism, the maximum stroke of restriction sub-piston 160.Between sub-piston 160 and valve bridge 400, a spring 177 can be set.

In the present embodiment, in valve bridge 400, be also provided with a decompression mechanism.Described decompression mechanism comprises the relief hole 152 on sub-piston 160.When the oil pressure in slave piston bore 190 increases, lubricating oil leakage by the gap between sub-piston 160 and hole 190 and the locating slot 137 on brake piston 160 and relief hole 152 increases thereupon, and the oil pressure that makes to act on sub-piston 160 is no more than designed predetermined value.

When needs engine braking, as shown in Figure 3, open brake control mechanism 50.By brake fluid networking, to braking drive organ 100 fuel feeding.Brake fluid networking comprises numerous oil supply galleries, as the otch 213 in the axial bore 211 in pitman arm shaft 205 and radial hole 212, rocking arm 210 and the cross-drilled hole 113 in oilhole 214 and valve clearance adjusting screw and vertical core 115 (communicating with the hole in resembling foot pad 114).Low-pressure oil is from oil supply gallery, by being arranged on the unidirectional delivery valve 172 on main piston 162, to the interior fuel feeding of master piston bore 415.Main piston 162 in the master piston bore 415 of valve bridge 400 in extended position as shown in Figure 1, the bottom surface, hole 446 of main piston 162 and master piston bore 415 forms a brake clearance 234 between (namely valve bridge 400), and the hydraulic channel 412 between master piston bore 415 and slave piston bore 190 is in an open position.

For simplicity's sake, the oil leab of motor does not show at this.Certainly, oil leab also can unite two into one with braking oil duct, adopts the different oil pressure fuel feeding of two-stage.When lubricated, adopt low oil pressure, such as, a bar or lower; During braking, adopt high oil pressure, such as, two bar or higher.

When the braking boss of cam 230 (compression discharges boss) 233 from interior basic circle 225 when rising; the main piston 162 in rocking arm 210 actuating valve bridges 400 is down shifted to the retracted position of master piston bore bottom surface 446 from the extended position of Fig. 1; the hydraulic channel 412 by between master piston bore 415 and slave piston bore 190, passes to sub-piston 160 by moving downward of main piston 162.Be positioned at the brake holder 125 on the valve bridge 400 of slave piston bore 190 tops, make valve bridge 400 can not increase because of the oil pressure in slave piston bore 190.Sub-piston 160 in the slave piston bore 190 of valve bridge 400 can only stretch out downwards, opens and is positioned at sub-piston 160 braking first row valve 3001 below.When cam 230 enters the top lift of braking boss 233, main piston 162 the master piston bore 415 of valve bridge 400 is interior arrive at hole downwards at the bottom of 446 retracted position (Fig. 2), block the entrance 472 of hydraulic channel 412, close the hydraulic channel 412 between master piston bore 415 and slave piston bore 190.Meanwhile, sub-piston 160 is at the interior extended position that arrives at downwards of slave piston bore 190 of valve bridge 400, and the stroke of sub-piston 160 is 130, and sub-piston 160 first row valve 3001 below is correspondingly opened a gap 330.Now, the brake load on sub-piston 160 cannot pass to main piston 162 by hydraulic channel 412, can only pass to the brake holder 125 on the valve bridge 400 that is positioned at slave piston bore 190 tops by valve bridge 400.Main piston 162 and exhaust valve actuator 200 (comprising rocking arm 210 and cam 230) do not bear brake load.When cam 230 declines from braking the top lift of boss 233, main piston 162 is up shifted to extended position from the retracted position in the master piston bore 415 of valve bridge 400, open the hydraulic channel 412 between master piston bore 415 and slave piston bore 190, the sub-piston 160 in slave piston bore 190 is along with main piston 162 moves up together.When main piston 162 the master piston bore 415 of valve bridge 400 interior on while getting back to extended position, sub-piston 160 the slave piston bore 190 of valve bridge 400 interior on get back to retracted position (Fig. 1).

When the integrated form exhaust boss 220 of cam 230 from interior basic circle 225 when rising; the main piston 162 in rocking arm 210 actuating valve bridges 400 is down shifted to the retracted position of master piston bore bottom surface 446 from the extended position of Fig. 1; the hydraulic channel 412 by between master piston bore 415 and slave piston bore 190, passes to sub-piston 160 by moving downward of main piston 162.Be positioned at the brake holder 125 on the valve bridge 400 of slave piston bore 190 tops, valve bridge 400 can not rise because of the oil pressure in slave piston bore 190.Sub-piston 160 in the slave piston bore 190 of valve bridge 400 can only stretch out downwards, opens and is positioned at sub-piston 160 first row valve 3001 below.When cam 230 enters the top top lift of boss 233 (be greater than braking) of integrated form exhaust boss 220, at the bottom of main piston 162 compressing master piston bore 446, actuating valve bridge 400 moves downward.Valve bridge 400 is separated with the brake holder 125 that is located thereon face, opens emptying passage 197 emptyings that communicate with slave piston bore 190 in valve bridge 400, and sub-piston 160 moves on to retracted position from extended position in the slave piston bore 190 of valve bridge 400.Valve bridge 400 passes to first row valve 3001 and second row valve 3002 by the motion at integrated form exhaust boss 220 tops, produces conventional exhaust valve motion.

If the braking boss of cam 230 also comprises exhaust gas recirculatioon boss 232, exhaust gas recirculatioon boss 232 is opened the process of first row valve 3001 by exhaust valve chain so, the process of opening first row valve 3001 by exhaust valve chain with above-mentioned compression release boss 233 is identical, at this, no longer repeats.If motor has enough exhaust back pressures, after increasing so exhaust gas recirculatioon boss 232, the braking force of motor is likely further improved.

When not needing engine braking, as shown in Figure 4, close brake control mechanism 50, stop to braking drive organ 100 fuel feeding.When cam 230 enters the top (being greater than the top lift that compression discharges boss 233) of integrated form exhaust boss 220, at the bottom of main piston 162 compressing master piston bore 446, actuating valve bridge 400 moves downward.Valve bridge 400 is separated with the brake holder 125 that is located thereon face, open emptying passage 197 emptyings that communicate with slave piston bore 190 in valve bridge 400, sub-piston 160 moves on to retracted position (Fig. 1) from extended position (Fig. 2) in the slave piston bore 190 of valve bridge 400.Valve bridge 400 passes to first row valve 3001 and second row valve 3002 by the motion at integrated form exhaust boss 220 tops, produces conventional exhaust valve motion.At cam 230, from the top of integrated form exhaust boss 220, entering its bottom gets back to the process of interior basic circle, sub-piston 160 remains on the retracted position shown in Fig. 1 (due to the upwards active force of exhaust valve spring 3101), main piston 162 remains on the retracted position shown in Fig. 2 (due to the downward active force of preloading spring 198), between the cam follower wheel 235 on rocking arm 210 and the interior basic circle 225 of cam 230, forms a gap.Due to this gap, the motion of braking boss (compression discharges boss 233 and exhaust gas recirculatioon boss 232) will can not pass to exhaust valve 300, only have the motion at integrated form exhaust boss 220 tops to pass to exhaust valve 300, produce conventional exhaust valve motion, the braking running of motor is disengaged.

As shown in Figure 3 and Figure 4, the position of the brake control mechanism 50 of compression-release engine braking device of the present invention in " opening " and " pass ".Solenoid valve 51 in figure is two-position three way type.When brake control mechanism 50 is opened (Fig. 3), the valve body of solenoid valve 51 is opened oil-feed port 111 downwards, close unloading port 222, the low-pressure oil of motor (lubricant oil) flows to braking drive organ 100 (Fig. 1 and Fig. 2) from brake fluid passage simultaneously.When brake control mechanism 50 is closed (Fig. 4), the valve body of solenoid valve 51 is upwards closed oil-feed port 111, open unloading port 222 simultaneously, the low-pressure oil of motor (lubricant oil) stops flowing to braking drive organ 100 (Fig. 1 and Fig. 2), and braking drive organ 100 is on the contrary from brake fluid passage and unloading port's 222 emptyings.Owing to being provided with emptying passage 197 (Fig. 1 and Fig. 2) in the slave piston bore 190 in valve bridge 400, completely likely use two two way solenoid valves, that is to say, do not need unloading port 222.

Fig. 5 has represented a kind of cam profile in compression-release engine braking device of the present invention, and comprising braking boss and integrated form exhaust boss 220, braking boss comprises that compression discharges boss 233 and exhaust gas recirculatioon boss 232.Compression discharges boss 233 and comprises three parts: ascent stage " A ", contour section " B " and descending branch " C ".Ascent stage " A " rises to the top lift of braking from the interior basic circle 225 of cam.Contour section " B " substantially remains unchanged the top lift of braking within a period of time.Descending branch " C " rolls back the interior basic circle 225 of cam from the top lift of braking.The effect of contour section " B " is to keep in the master piston bore 415 of main piston 162 at valve bridge 400 446 retracted position (Fig. 2) at the bottom of hole in when braking, close the hydraulic channel 412 between master piston bore 415 and slave piston bore 190, brake load on sub-piston 160 cannot pass to main piston 162 by hydraulic channel 412, can only pass to the brake holder 125 being located thereon by valve bridge 400.Exhaust valve actuator 200 (comprising rocking arm 210 and cam 230) does not bear brake load like this, has reduced the stressed of exhaust valve actuator 200 and wearing and tearing, has increased reliability and the durability of motor.

Exhaust gas recirculatioon boss 232 also can be designed as the shape that compression discharges boss 233.But due to during exhaust gas recirculatioon, exhaust valve stressed much smaller than compression deenergized period.Therefore the impact of load can not be considered in the design of the profilogram shape of exhaust gas recirculatioon boss 232.

Integrated form exhaust boss 220 is divided into bottom and top (double dot dash line in Fig. 5 separates them).The bottom of integrated form exhaust boss 220 is transition portion, approaches with high with braking boss; The top of integrated form exhaust boss 220 approaches identical with the conventional boss of motor.Like this, when non-braking (conventional igniting) running, the bottom of integrated form exhaust boss 220 is all skipped or loses because of the gap 234 (Fig. 1) of exhaust valve chain inside together with the motion of braking boss (compression discharges boss 233 and exhaust gas recirculatioon boss 232), can not pass to exhaust valve 300; Only have the motion at the top of integrated form exhaust boss 220 to be delivered to exhaust valve 300, produce conventional valve elevator moving.

Fig. 6 has represented the lifting curve of a kind of exhaust valve in compression-release engine braking device of the present invention and the lifting curve of intake valve.The starting point that the conventional valve of engine exhaust port rises curve 220m is 225a, and terminal is 225b, and its top lift is approximately 220b.Supposing does not have emptying passage 197 (Fig. 1 and Fig. 2) in the slave piston bore 190 in valve bridge 400, the starting point that the main valve of the increasing being produced by the conventional exhaust boss 220 strengthening during engine braking so rises curve 220v is 225h, terminal is 225c, and its top lift 220e is 220a and 220b sum.Due to emptying passage 197, the valve of braking exhaust valve 3001 rises bottom 220a and the transition point 220t between the 220b of top that curve rises curve 220v at the main valve of increasing and rises curve 220m transition to main valve, at 220s point and main valve, rise curve 220m fusion, when terminal 225b ratio has emptying passage, do not close in advance.

When engine braking operates, the motion of the braking boss of cam (exhaust gas recirculatioon boss 232 and compression discharge boss 233), by rocking arm 210, pass to main piston 162 (Fig. 1 and Fig. 2), the hydraulic channel 412 that moves through of main piston 162 is passed to sub-piston 160 and sub-piston 160 exhaust valve 3001 below, and the brake valve that produces exhaust gas recirculatioon rises 232v and compresses the brake valve discharging and rises 233v.The starting point that the brake valve of exhaust gas recirculatioon rises 232v is 225d, is positioned at the later stage of the aspirating stroke of motor, namely when the valve of intake valve rises curve 280v and is tending towards cutting out; The terminal that the brake valve of exhaust gas recirculatioon rises 232v is 225e, is positioned at the early stage of the compression stroke of motor.The starting point that the brake valve that compression discharges rises 233v is 225f, is positioned at the later stage of the compression stroke of motor; The terminal that the brake valve that compression discharges rises 233v is 225g, is positioned at the early stage of the expansion stroke of motor.Valve rises curve and circulates between 0～720 °, and 0 ° and 720 ° is same point.

When the integrated form exhaust boss 220 of cam 230 is from interior basic circle 225 when rising (Fig. 5), rocking arm 210 promotes main pistons 162 (Fig. 1 and Fig. 2), and main piston 162 promotes sub-pistons 160, and sub-piston 160 promotes exhaust valves 3001 and moves downward.When cam 230 enters the top (being greater than the top lift of braking boss 233) of integrated form exhaust boss 220 (Fig. 5), main piston 162 starts actuating valve bridge 400 and moves downward (Fig. 2).Valve bridge 400 is separated with brake holder 125, open emptying passage 197 emptyings, sub-piston 160 moves on to retracted position from extended position, the valve of braking exhaust valve 3001 rises curve and from transition point 220t to main valve, rises curve 220m transition (Fig. 6), finally at terminal 225b, close, the terminal 225c when not unloading circulation road is greatly leading.So just reduce the lift of exhaust valve at the top dead center position of engine exhaust strokes, avoided the collision of exhaust valve and piston, also increased braking force, reduced the temperature of cylinder internal.

Fig. 7 has represented the another kind of cam profile of compression-release engine braking device of the present invention.The difference of the cam profile shown in this cam profile and Fig. 5 is that compression discharges boss 233.Front two-part that compression discharges boss 233 also comprise ascent stage " A " and contour section " B ", but do not drop to interior basic circle 225 in contour section " B " descending branch " D " afterwards, but transition imports integrated form exhaust boss 220.

Fig. 8 has represented another cam profile of compression-release engine braking device of the present invention.The difference of the cam profile shown in this cam profile and Fig. 5 is also that compression discharges boss 233.Front two-part that compression discharges boss 233 comprise ascent stage " A " and contour section " B " equally, but do not decline afterwards at contour section " B ", but by a slow section " E " that rises, import integrated form exhaust boss 220.Cam 230 enters the slow section " E " that rises from contour section " B " of braking boss, main piston 160 down promotes valve bridge 400 (Fig. 2) from 446 retracted position at the bottom of the master piston bore of valve bridge 400, valve bridge 400 is separated with the brake holder 125 being positioned on valve bridge 400, emptying passage 197 emptyings in open auxiliary piston hole 190 top valve bridges 400, sub-piston 160 migration retracted position upwards in the slave piston bore 190 of valve bridge 400, sub-piston 160 exhaust valve 3001 below and then upwards cuts out.That is to say, unloading circulation road 197 and will be opened in the slow section " E " that rises in the interior slave piston bore 190 of valve bridge 400, the brake valve of braking exhaust valve 3001 rises likely from high threshold liter and drops to zero (cutting out).

Embodiment 2:

As shown in Figure 9 and Figure 10, second of compression-release engine braking device of the present invention embodiment position of cam in interior basic circle when non-braking and during braking.The present embodiment is that from first embodiment's difference the present embodiment has adopted a kind of different brake holder 125.The effect that is positioned at valve bridge 400 brake holder 125 above mainly contains two: the one, when engine braking, support valve bridge 400, moving upward of prevention or limiting valve bridge 400, the emptying passage 197 of sealing slave piston bore 190 tops, bears from braking exhaust valve 3001 and passes the brake load of coming; The 2nd, within each cycle of engine braking, when the top of integrated form exhaust boss 220 promotion valve bridge moves down, emptying passage 197 emptyings of open auxiliary piston hole 190 tops, the valve of the braking exhaust valve 3001 of resetting rises curve.Certainly, emptying mechanism is also for removing the braking running of motor.

The brake holder 125 of the present embodiment also comprises other link, as transition piston 161.Transition piston 161 is placed in valve bridge 400 transition piston hole 191 above slidably, forms a kind of automatic backlash compensation mechanism.Emptying passage 197 is above slave piston bore 190, and (size of two piston holes is definite as required, and its phasing not of uniform size is same) is connected transition piston hole 191 with slave piston bore 190.Transition piston 161 is interior has increased an emptying passage 196.The moving range of transition piston 161 is controlled by compressing tablet 178.Compressing tablet 178 is fixed on valve bridge 400 by screw 179.The moving range of transition piston 161 also can be passed through alternate manner, as snap ring etc. is controlled.Above transition piston 161, resembling foot pad 1142 with another link of brake holder 125 is connected.Resembling foot pad 1142 is enclosed within on the pressure ball of pressure ball bar 1103.Pressure ball bar 1103 also can be combined with adjusting screw 1102.Resemble between foot pad 1142 and pressure ball and can have certain relative movement or gap, spring 177 will resemble foot pad 1142 biased downward on transition piston 161, sealing emptying passage 196 and 197 (machine oil cannot from transition piston hole 191 and slave piston bore 190 toward external leakage).

When not needing engine braking, as shown in Figure 4, close brake control mechanism 50, stop to braking drive organ 100 fuel feeding, braking device is in non-braking state as shown in Figure 9.Master piston bore 415 and slave piston bore 190 due to emptying mechanism in draining state.Main piston 162 is pressed against the retracted position of master piston bore 415 bottom surfaces 446 under the effect of preloading spring 198, between cam follower wheel 235 and the interior basic circle 225 of cam 230, forms a gap 134.Sub-piston 160 is pressed against the retracted position of slave piston bore 190 bottom surfaces, and sub-piston 160 exhaust valve 3001 is below in the closed position.The transition piston 161 of brake holder 125 is pressed against the retracted position of transition piston hole 191 bottom surfaces under the effect of spring 177.When cam 230 enters braking boss 232 or braking boss 233 from interior basic circle 225, gap 134 due to exhaust valve chain inner (between cam follower wheel 235 and cam 230), the motion of braking boss 232 or braking boss 233 is skipped or loses, and can not pass to exhaust valve 300.(Fig. 5 when cam 230 enters the top of integrated form exhaust boss 220,7 and 8), move through rocking arm 210, main piston 162, valve bridge 400 and the sub-piston 160 of cam pass to exhaust valve 300 (first row valve 3001 and second row valve 3002) in the mode of the solid chain type of machinery, produce conventional exhaust valve motion.

When needs engine braking, as shown in Figure 3, open brake control mechanism 50, to braking drive organ 100 fuel feeding.Braking device enters braking state as shown in figure 10 from non-braking state as shown in Figure 9.Low-pressure oil, from oil supply gallery, by oil feed non-return valve 172, enters master piston bore 415.Main piston 162, under oil pressure effect, up moves on to extended position from the retracted position of master piston bore 415 bottom surfaces 446 of valve bridge 400, promotes rocking arm 210 and clockwise rotates, until cam follower wheel 235 contacts with the interior basic circle 255 of cam 230.Now, between the bottom surface, hole 446 (namely valve bridge 400) of main piston 162 and master piston bore 415, form a brake clearance 234 (corresponding with the gap 134 of Fig. 9), open the opening 472 of the hydraulic channel 412 between master piston bore 415 and slave piston bore 190.Oil flows to the transition piston hole 191 into slave piston bore 190 and its top.Oil pressure overcomes the active force of spring 177, and promotion transition piston 161 upwards presses and resembles foot pad 1142, sealing emptying passage, and the machine oil in prevention transition piston hole 191 and slave piston bore 190 makes progress and leaks.Between main piston 162 and sub-piston 160, just formed hydraulic pressure link like this, main piston 162 moving downward in the master piston bore 415 of valve bridge 400, by the mode with hydraulic type, by hydraulic channel 412, pass to the sub-piston 160 in valve bridge 400 and slave piston bore 190, and then pass to first row valve 3001 below.

Cam 230 is opened the whole process of braking exhaust valve 3001 and non-braking exhaust valve 3002 by exhaust valve chain, basic identical with the first embodiment no longer repeated at this.

Above-mentioned explanation has disclosed a kind of new compression-release engine braking device and method.Above-mentioned mode of execution, should not be regarded as limitation of the scope of the invention, but as representing concrete illustrations more of the present invention, many other develop all and likely therefrom produce.For instance, the compression-release engine braking device here and method, not only can, for overhead camshaft type engine, also be applicable to push rod engine.Also have, unidirectional delivery valve 172 can adopt different forms, as ball valve, dish valve etc.Unidirectional delivery valve 172 also can be placed in different positions, such as being placed in main piston 162.Because the main piston 162 in valve bridge 400 (by valve clearance controlling mechanism) is close to rocking arm 210 all the time, unidirectional delivery valve 172 can also be placed in the oil supply gallery of main piston 162 tops, such as in oil duct 214 in rocking arm 210.The oil supply gallery that 172 of unidirectional delivery valves allow oil stream one direction to swim from it enters in main piston 162 master piston bore 415 below.

In addition except the emptying mechanism that the emptying passage 197 by slave piston bore 190 tops and brake holder 125 form, can be also the oil drain valve of other form.The oil drain valve of emptying mechanism when braking boss promotes main piston 162 make relative sliding in braking casing in closed condition.While further promoting main piston 162 motion at the top of integrated form exhaust boss, the oil drain valve of emptying mechanism opens emptying.

Also have, main piston 162, sub-piston 160 and transition piston 161 can adopt different forms, as " H " type and T-shape etc.; The exhaust valve of braking can be first row valve 3001, can be also second row valve 3002.

In addition, the installation of brake holder 125 also can have various ways, except being fixed on different parts and the position of motor, also can be integrated in the movement parts of motor.Brake holder 125 such as the second embodiment, can be integrated on rocking arm 210.Now, sub-piston 160 is positioned on second row valve 3002.Transition piston 161, except backlash compensation, also plays the effect of the second main piston.That is to say, during braking, the foot 114 that resembles on rocking arm 210 promotes main piston 162, and meanwhile, the foot 1142 that resembles of the brake holder 125 on rocking arm 210 promotes transition piston 161.Then, together with main piston 162 links by hydraulic pressure with transition piston 161, promote sub-piston 160, open second row valve 3002.The link of brake holder 125 also can be selected different patterns, or adopts different seal approach, as increased Sealing etc., guarantees the sealing to emptying passage.

Also have, main piston 162 is blocked the mode of the entrance 472 of hydraulic channel 412 also can be different.Such as below main piston 162 (rather than side), when main piston 162 moves on to the retracted position of master piston bore bottom surface 446, the bottom surface of main piston 162 covers entrance 472 by 472 designs of the entrance of hydraulic channel 412.

In addition,, except by valve bridge 400 conduct braking casings, also can there is other form.Such as be fixed on the overhead type braking casing on motor.Therefore, scope of the present invention should not decided by above-mentioned concrete illustration, but is decided by claim.

Claims

1. a compression releasing engine braking, comprise a process of utilizing the exhaust valve chain unlatching exhaust valve of motor, described exhaust valve chain comprises cam, rocking arm and valve bridge, in the exhaust valve of described motor, include a first row valve and a second row valve, in described cam, contain at least one braking boss, described braking boss comprises that an interior basic circle from cam rises to the ascent stage of maximum lift and contour section of the maximum lift described in a maintenance, in described rocking arm, be provided with an oil supply gallery, it is characterized in that: the mediad upper shed at described valve bridge arranges a master piston bore, one end at valve bridge arranges a slave piston bore under shed, between described master piston bore and slave piston bore, connect a hydraulic channel is set, master piston bore inner sliding type a main piston is set, main piston has an extended position and a retracted position with respect to master piston bore, slave piston bore inner sliding type a sub-piston is set, the upper end of main piston is connected with described rocking arm, an oil circuit is set in main piston, the upper end of described oil circuit is communicated with the oil supply gallery in described rocking arm, the lower end of oil circuit is communicated with master piston bore, between master piston bore and oil supply gallery, or a unidirectional delivery valve is set within oil supply gallery, the fuel feeding direction of described unidirectional delivery valve is from oil supply gallery to master piston bore, the lower end of sub-piston is connected with described first row valve, the downside of the valve bridge the other end is connected with described second row valve, upside in the valve bridge one end at slave piston bore place arranges a brake holder, cam also includes a descending branch, the starting point of described descending branch is connected to the described end of contour section, the terminal of descending branch is got back to or near the interior basic circle of cam, or, on cam, be provided with an integrated form exhaust boss, on braking boss, be provided with a slow section that rises, the described slow starting point that rises section is connected to the end of contour section, the slow terminal that rises section is imported to described integrated form exhaust boss, at the described exhaust valve chain that utilizes motor, open in the process of exhaust valve, first, by described oil supply gallery and unidirectional delivery valve to master piston bore fuel feeding, main piston is placed in to extended position, open the hydraulic channel between master piston bore and slave piston bore, then, utilize the ascent stage of braking boss in cam to drive described rocking arm, make rocking arm promote main piston and shift to retracted position from extended position, utilize described brake holder to stop on valve bridge moves simultaneously, utilize the hydraulic pressure in described hydraulic channel that the motion of main piston is passed to sub-piston, force described sub-piston to stretch out in slave piston bore downwards, open first row valve, afterwards, utilize contour section of driving rocking arm braking boss in cam, main piston is remained on retracted position in master piston bore, blocking-up master piston bore is by described hydraulic channel and the hydraulic pressure transfer between slave piston bore, sub-piston is remained on to the extended position in slave piston bore, the open mode that keeps first row valve, utilize the brake load on brake holder carrying sub-piston simultaneously.

2. compression releasing engine braking as claimed in claim 1, it is characterized in that: in the valve bridge one end at slave piston bore place, at least one emptying passage is set, the lower end of described emptying passage is communicated with slave piston bore, utilize the upper end open of the lower end closed emptying passage of described brake holder.

3. compression releasing engine braking as claimed in claim 1, it is characterized in that: in cam, brake boss after contour section, enter in the process of descending branch, utilize rocking arm to do reversing motion, make main piston shift to extended position from retracted position, open the opening of hydraulic channel in master piston bore, connect the hydraulic pressure transfer between master piston bore and slave piston bore, sub-piston is moved to retracted position under the active force of first row valve.

4. compression releasing engine braking as claimed in claim 1, is characterized in that: the axial setting by the oil circuit in main piston along main piston, is arranged on the lower ending opening of oil circuit in the lower end surface of main piston.

5. compression releasing engine braking as claimed in claim 2, it is characterized in that: in cam, brake boss after contour section, enter in the process of slow liter section, utilize the slow section that rises of braking boss to drive described rocking arm, make rocking arm inside contract back locational main piston and down promote valve bridge by being positioned at master piston bore, make the valve bridge one end at slave piston bore place separated with the described brake holder that is located thereon side, open the upper end open emptying of emptying passage, reduce the hydraulic pressure in slave piston bore, make sub-piston under the active force of first row valve in slave piston bore migration retracted position upwards, make the first row valve migration closed position that makes progress.

6. compression releasing engine braking as claimed in claim 1, is characterized in that: the process that the described exhaust valve chain that utilizes motor is opened exhaust valve comprises the following steps:

11) the braking boss of cam rolls back interior basic circle from top lift,

7. compression releasing engine braking as claimed in claim 2, is characterized in that: it is further comprising the steps of that the described exhaust valve chain that utilizes motor is opened the process of exhaust valve:

4) the emptying passage emptying of open auxiliary piston hole top,

8. compression releasing engine braking as claimed in claim 1, it is characterized in that: when main piston slides to extended position from retracted position in master piston bore, utilize main piston to open hydraulic channel and be positioned at the opening in master piston bore, when main piston slides to retracted position from extended position in master piston bore, utilize main piston to close hydraulic channel and be positioned at the opening in master piston bore.

9. compression releasing engine braking as claimed in claim 2, is characterized in that: described emptying channel setting has an outlet, and when valve bridge is moved down by actuated by cams, valve bridge is separated with brake holder, opens the outlet of described emptying passage.

10. compression releasing engine braking as claimed in claim 1, is characterized in that: described brake holder is fixed on motor, and described brake holder comprises link, and described link is positioned at the top of valve bridge.

11. compression releasing engine brakings as claimed in claim 1, is characterized in that: described brake holder is integrated on described rocking arm, and described brake holder comprises link, and described link is positioned at the top of valve bridge.

12. compression releasing engine brakings as claimed in claim 1, it is characterized in that: in described braking boss, include a compression and discharge boss, described compression discharges boss and starts to rise from the interior basic circle of cam in the later stage of the compression stroke of motor, and reach extreme higher position at the near of motor, under the early stage of the expansion stroke of motor, roll back the interior basic circle of cam.

13. compression releasing engine brakings as claimed in claim 1, it is characterized in that: in described braking boss, include a compression and discharge boss and an exhaust gas recirculatioon boss, described compression discharges boss and starts to rise from the interior basic circle of cam in the later stage of the compression stroke of motor, and reach extreme higher position at the near of motor, under the early stage of the expansion stroke of motor, roll back the interior basic circle of cam, described exhaust gas recirculatioon boss started to rise from the interior basic circle of cam in the later stage of the aspirating stroke of motor, under the early stage of the compression stroke of motor, roll back the interior basic circle of cam.

14. compression releasing engine brakings as claimed in claim 1, it is characterized in that: an integrated form exhaust boss is set on described cam, in described braking boss, include a compression and discharge boss, described compression discharges boss and starts to rise from the interior basic circle of cam in the later stage of the compression stroke of motor, and rose to extreme higher position before the compression stroke top dead center of motor, in the remaining period of compression stroke of motor and the initial stage of the expansion stroke of motor, keep described extreme higher position, under the remaining period of the expansion stroke of motor, roll back the interior basic circle of cam or import integrated form exhaust boss, described integrated form exhaust boss is comprised of bottom and top, the bottom of integrated form exhaust boss approaches with high with braking boss, the top of integrated form exhaust boss approaches identical with the conventional boss of motor.

15. compression releasing engine brakings as claimed in claim 1, it is characterized in that: in described braking boss, include an exhaust gas recirculatioon boss, described exhaust gas recirculatioon boss started to rise from the interior basic circle of cam in later stage of the aspirating stroke of motor, rolled back the interior basic circle of cam under the early stage of the compression stroke of motor.

16. compression releasing engine brakings as claimed in claim 1, it is characterized in that: an integrated form exhaust boss is set on described cam, in described braking boss, include a compression and discharge boss, described compression discharges boss and starts to rise from the interior basic circle of cam in the latter half of the compression stroke of motor, and rose to extreme higher position before the compression top center of motor, in the remaining period of compression stroke of motor and the described extreme higher position of maintenance in the early stage of the expansion stroke of motor, in the remaining period of the expansion stroke of motor, rise and import integrated form exhaust boss.

17. compression releasing engine brakings as claimed in claim 1, it is characterized in that: utilize a preloading spring in exhaust valve chain inside, to keep, by the retracted position of main piston and the exhaust valve chain brake clearance of extended position generation, utilizing not following and impacting of described exhaust valve chain brake clearance elimination exhaust valve chain inside.

18. 1 kinds of compression-release engine braking devices, comprise brake control mechanism and braking drive organ, it is characterized in that: described brake control mechanism comprises a control valve being connected with hydraulic pressure generation device, braking drive organ comprises braking casing, oil feeding mechanism, emptying mechanism and brake cam, in described braking casing, be provided with master piston bore and slave piston bore, between described master piston bore and slave piston bore, be provided with the hydraulic channel of a connection, be provided with main piston master piston bore inner sliding type, be provided with sub-piston slave piston bore inner sliding type, described oil feeding mechanism comprises oil supply gallery and unidirectional delivery valve, control valve in described brake control mechanism is connected with the entrance of described oil supply gallery, the outlet of oil supply gallery is connected with master piston bore, described unidirectional delivery valve is arranged between oil supply gallery or oil supply gallery and master piston bore, the fuel feeding direction of unidirectional delivery valve is to enter master piston bore from oil supply gallery, described emptying mechanism comprises Yi Ge oil drain valve, described oil drain valve is communicated with slave piston bore, in described brake cam, contain at least one braking boss, described braking casing consists of valve bridge, described master piston bore is arranged in a upward opening of described valve bridge central authorities, described slave piston bore is arranged on of one end of valve bridge under shed, described hydraulic channel is arranged in valve bridge and is communicated with master piston bore and slave piston bore, described main piston is arranged in master piston bore, described sub-piston is arranged in slave piston bore, the upper end of main piston is connected with the rocking arm of motor, in described rocking arm, be provided with an oil supply gallery, in main piston, be provided with an oil circuit, the upper end of described oil circuit communicates with the oil supply gallery in described rocking arm, the lower end of oil circuit communicates with master piston bore, described unidirectional delivery valve is arranged between master piston bore and oil supply gallery or within oil supply gallery, the fuel feeding direction of described unidirectional delivery valve is from oil supply gallery to master piston bore, the upside of the valve bridge one end at slave piston bore place is provided with a brake holder, the valve bridge one end at slave piston bore place is provided with at least one emptying passage, one end of described emptying passage communicates with slave piston bore, the other end of emptying passage is by the lower end closed of brake holder, on described brake cam, be provided with integrated form exhaust boss.

19. compression-release engine braking devices as claimed in claim 18, it is characterized in that: the lower end of sub-piston is connected with a first row valve in engine exhaust port, the downside of the valve bridge the other end is connected with a second row valve in engine exhaust port.

20. compression-release engine braking devices as claimed in claim 18, is characterized in that: described brake holder is fixed on motor, and described brake holder comprises link, and described link is positioned at the top of valve bridge.

21. compression-release engine braking devices as claimed in claim 18, is characterized in that: described brake holder is integrated on rocking arm, and described brake holder comprises link, and described link is positioned at the top of valve bridge.

22. compression-release engine braking devices as described in claim 20 or 21, it is characterized in that: the link of described brake holder comprises transition piston, described transition piston is placed in the transition piston hole of valve bridge slidably, and described transition piston hole is positioned on described slave piston bore.

23. compression-release engine braking devices as claimed in claim 18, it is characterized in that: in described braking boss, include a compression and discharge boss, described compression discharges boss and starts to rise from the interior basic circle of cam in the later stage of the compression stroke of motor, and reach extreme higher position at the near of motor, under the early stage of the expansion stroke of motor, roll back or near the interior basic circle of cam.

24. compression-release engine braking devices as claimed in claim 18, it is characterized in that: in described braking boss, include a compression and discharge boss and an exhaust gas recirculatioon boss, described compression discharges boss and starts to rise from the interior basic circle of cam in the later stage of the compression stroke of motor, and reach extreme higher position at the near of motor, under the early stage of the expansion stroke of motor, roll back or near the interior basic circle of cam, described exhaust gas recirculatioon boss started to rise from the interior basic circle of cam in the later stage of the aspirating stroke of motor, under the early stage of the compression stroke of motor, roll back the interior basic circle of cam.

25. compression-release engine braking devices as claimed in claim 18, it is characterized in that: on described cam, be provided with an integrated form exhaust boss, in described braking boss, include a compression and discharge boss, described compression discharges boss and starts to rise from the interior basic circle of cam in the later stage of the compression stroke of motor, and rose to extreme higher position before the compression stroke top dead center of motor, in the remaining period of compression stroke of motor and the initial stage of the expansion stroke of motor, keep described extreme higher position, under the remaining period of the expansion stroke of motor, roll back the interior basic circle of cam or import integrated form exhaust boss, described integrated form exhaust boss is comprised of bottom and top, the bottom of integrated form exhaust boss approaches with high with braking boss, the top of integrated form exhaust boss approaches identical with the conventional boss of motor.

26. compression-release engine braking devices as claimed in claim 18, it is characterized in that: in described braking boss, include an exhaust gas recirculatioon boss, described exhaust gas recirculatioon boss started to rise from the interior basic circle of cam in later stage of the aspirating stroke of motor, rolled back the interior basic circle of cam under the early stage of the compression stroke of motor.

27. compression-release engine braking devices as claimed in claim 18, it is characterized in that: on described cam, be provided with an integrated form exhaust boss, in described braking boss, include a compression and discharge boss, described compression discharges boss and starts to rise from the interior basic circle of cam in the latter half of the compression stroke of motor, and rose to extreme higher position before the compression top center of motor, in the remaining period of compression stroke of motor and the described extreme higher position of maintenance in the early stage of the expansion stroke of motor, in the remaining period of the expansion stroke of motor, rise and import integrated form exhaust boss.

28. compression-release engine braking devices as claimed in claim 18, is characterized in that: in described braking drive organ, be provided with a preloading spring.

29. compression-release engine braking devices as claimed in claim 28, is characterized in that: one end of described preloading spring is relative with described motor to be fixedly installed, and the other end of preloading spring acts on one end of described rocking arm.

30. compression-release engine braking devices as claimed in claim 18, is characterized in that: in described braking drive organ, be provided with an automatic backlash compensation mechanism.