Summary of the invention
The purpose of this invention is to provide a kind of method of controlling outlet valve more accurately, it is included in the process of outlet valve motion and controls.
For this reason, feature of the present invention is that the valve rod displacement and the length travel of the valve rod of control valve longitudinally of outlet valve is proportional, and valve rod can be at complete opening and close fully between select location, and outlet valve close and the enable possition between, the valve rod of outlet valve and the valve rod of control valve are synchronized with the movement basically.
The proportional length travel of valve rod and valve rod causes the adjustment of any valve rod all to be changed into the corresponding sports of outlet valve.Therefore, between the current location of the current location of valve rod and valve rod, have direct correlation, and, the adjustment campaign of outlet valve only depends on the adjustment of valve rod, simultaneously, when valve rod remained on certain position, it is liquid body variation in pressure or the influence of action time not.When valve rod was between extreme position, valve rod can make valve rod be positioned the neutral position, allows the motion of direct control valve rod.Because valve rod further motion carries out basically simultaneously with valve rod, in the process of engine cycles work, outlet valve can move as required, and it is independent of the current rotational velocity of motor.
Best, the terminal of exhaust valve closure motion is by the control valve ACTIVE CONTROL, and replacement makes the valve rod braking by throttling action, and this is because throttling action will cause energy loss.If the final stage of control valve control closing movement, and make the valve rod braking thus, the energy that arrives the driver needs of outlet valve from high-pressure liquid reduces.So that form the throttle clearance, the structure of driver is simplified except that needs precise forming parts.
In addition,, can change to next work cycle from a work cycle of motor in the speed of the predetermined part outlet valve valve rod of motion path.For example, at the initial stage of opening movement, the speed of outlet valve can increase, and quickens the unlatching of valve thus.The valve rod of fast moving leaves closed position with high acceleration, enters the enable possition, because the outflow zone enlarges rapidly, the amount of being heated of valve disc and fixed valve base is reduced.In the process of motor operation, the possibility of exhaust valve variations speed is allowed current operating conditions is adjusted continuously.
According to method provided by the invention, when valve rod remained on the enable possition, before arriving full open position, because the opening movement of outlet valve can stop at the neutral position of unlatching, its advantage was the condition that can change operation as required.Reduce the consumption of liquid stream thus, and reduced the consumption of energy when pushing outlet valve thus.When motor moved under the partial load effect, air displacement was smaller in the process of each engine operational cycle, and this depends on the type of motor, and the rotating speed of motor can be lower, provided the long time for discharging gas.This working environment allows to reduce the outflow zone.
Accurately the possibility of control stem movement is suitable for keeping the final stage of valve rod at closing movement, pauses a period of time at ventilation position; At this ventilation position, between the valve base surface of outlet valve, have an airspace, after this, valve rod moves into its complete closed position.Keep outlet valve to open a period of time near its complete closed position, i.e. so-called stand-by period or dwell time, the quite cold air flows of guiding is passed through valve base surface thus, and valve base surface is cooled basically.Cause the mean temperature of valve material to reduce thus, prolonged the working life of outlet valve, and can adopt comparatively cheap seat material.The durability of valve seat further improves, and by the air blast of ventilating air, can blow away the particulate of any remnants, therefore reduces indenture to occur.
The OK range of stand-by period is 4~50 milliseconds (ms).This time range is applicable to have wide-aperture low speed or medium-speed engine.If the stand-by period becomes less than 4 milliseconds, the cool condition that need this moment becomes quite abominable, if the opposite stand-by period greater than 50 milliseconds, the air consumption that is used to cool off is excessive.
Best, valve rod and valve base surface distance each other at ventilation position are 0.02~0.5 millimeter, the speed air flow that passes through airspace that provides thus reaches velocity of sound, and this is apart from preferably 0.05~0.2 millimeter, reduce the volume that flows out air quantity thus, so that it is unaffected basically to keep-up pressure.
The indenture that occurs can further reduce, and its means are the final stage at closing movement, at first make valve rod move to the position of closing basically, and valve rod is moved to opening direction momently immediately, and then enter its complete closed position.By at first carrying out the effect near complete closed position, any particle that exists between valve base surface is squeezed into and is the dust-like material, when valve rod is opened subsequently momently, stronger air stream occurs, blows away crushed dust-like material and waste gas.In subsequent step, complete throttle down, valve base surface no longer includes particulate, prevents the appearance of indenture thus.
For the unloading of limit load air, cooling and cleaning action for valve base surface can limit by the time, so that occur in the short time towards the of short duration motion of opening direction and the motion that enters complete closed position, 1/10th of this time ratio exhaust valve opening time cycle also will lack.
The invention still further relates to the outlet valve that is used for internal-combustion engine, it comprises the valve rod with hydraulic unit driver, described hydraulic unit driver has the fixed pressure cylinder, described pressure cylinder has at least one first pressure chamber and an associated actuator piston, and the control valve with control valve housing and control valve valve rod can be communicated with high-pressure mouth or the low pressure port in first pressure chamber and the control valve housing at least.
Structure by such structure outlet valve can obtain more accurate control, so that the motion of outlet valve valve rod between exhaust valve closure and enable possition is synchronous with the length travel of control valve valve rod basically, and the length travel of the length travel of outlet valve valve rod and control valve valve rod is proportional.During when valve rod with position at needs of the housing of valve rod, described position is determined that by the current location of valve rod this moment, control valve can not produce effect in simple mode under the fluid power effect by housing and together displacement of valve rod.
Best, the control valve housing can not longitudinally move with respect to exhasut valve stem, so housing and valve rod displacement in identical motion, that is, motion is than being 1: 1; And the valve rod length travel becomes 1: 1 ratio with the valve rod length travel.Alternatively, the displacement of valve rod can increase with respect to the displacement of control valve housing, and for example producing predetermined displacement movement ratio is 1: 2 or 1: 3, so the control valve valve rod has quite short stroke.
In simple especially structure, actuator piston constitutes the control valve housing.In another kind of simple structure, the top of valve rod constitutes the control valve housing.By making driver itself directly not have middle coupling element, therefore the control of outlet valve has been become directly and do not had delay factor by control valve valve rod control.The controlling component of minimum number provides extreme high reliability.
In one embodiment, the control valve valve rod is installed like this, and it is not vertically moved on the movably magnet component of linear motor, and the fixed coil parts of linear motor are installed with coaxial manner as the extension of exhasut valve stem.The advantage that adopting linear motor to adjust the control valve valve rod provides is a structure of having simplified mechanical component, because linear motor can freely be controlled the instantaneous or current location and the movement velocity thereof of movable part according to the electrical signal from control unit.In addition, in running, valve rod can be by the cam drive on the camshaft, but, this need have between the bent axle of camshaft and motor and is synchronized with the movement, and therefore in the work cycle process of motor, the motor pattern that freely change outlet valve is restricted.
When adopting linear motor, be preferably in close and full open position between, the movable part of linear motor has the stroke longer than the maximum moving distance of outlet valve.The advantage that provides thus is can compensate because the variation of the outlet valve length that factors vary such as wearing and tearing, temperature cause.Because the characteristic of linear motor can change at the terminal point near zone of movement position, this structure also provides point-device control mode.
Embodiment
Fig. 1 represents the top of cylinder of internal-combustion engine 1, and described internal-combustion engine can be two strokes or four stroke engine, and it has big cylinder bore diameter, and for example cylinder bore diameter is at least 200 millimeters, and the dimensional range of cylinder bore diameter is 240~1200 millimeters usually.For example, this internal-combustion engine can be to be used to promote boats and ships or supercharging, normal pressure, the two stroke crosshead engines of the power generation equipment that is used for fixing.Outlet valve 2 is installed in the cylinder head 3 of cylinder the topmost part.By the waste gas in the unidirectional exhaust eliminating cylinder, relief opening is positioned at the bottom of cylinder.Outlet valve also can be positioned at other position beyond the cylinder head central authorities, for example, on the sidewall of cylinder, a plurality of outlet valves is installed on same cylinder head perhaps.
Outlet valve comprises the valve rod 4 with valve disc, and valve disc has last ring-shaped valve seats surface, and this ring-shaped valve seats surface can be docked with the valve base surface of the fixing downward setting at cylinder head 3 places by sealing means.At the valve closing position, outlet valve stops between combustion chamber 5 and the exhaust passage 6 and is communicated with.In the valve opening position, valve rod 4 along it vertically to bottom offset.
High-pressure conduit 7 with high pressure liquid stream is with high pressure liquid stream, for example, pressure range clung to, is generally 150~300 crust 100~500 fluids guiding enters the high-pressure mouth of controlling in valve chamber or the housing 8, as shown in Figure 5, in this embodiment, control valve housing and valve rod 4 form one.Low-pressure tube 10 is connected the low pressure port 11 and the reflow pipe that is used for liquid stream in the control valve housing.Reflow pipe in the top of cylinder head 3 side and valve housing bottom is connected low-pressure tube 10, so that get rid of the fluid of any leakage.Low-pressure tube can center on the coaxial setting of high-pressure conduit, and in big-block engine, this is outstanding especially advantage, and wherein the passage from the outlet valve housing arrives high-pressure conduit downwards, and is parallel to the motor setting, and its length has several meters long.High-pressure conduit also can be to fuel jet driver feed streams.Except by with low-pressure tube and the coaxial setting of high-pressure conduit to obtain the bigger space, under the ruined situation of high-pressure conduit, low-pressure tube can also be as the protection barrier that is provided with around high-pressure conduit.
In embodiment as shown in the figure, pneumatic spring piston 13 is fixed on the valve rod 4, and be arranged to can displacement in pneumatic spring cylinder 5, and therefore, pneumatic spring chamber 14 is positioned at the below of piston, and supplies with pressurized air from pneumatic tube 15.Pneumatic spring is with the active force that makes progress, along the direction of closed position, and continuous action is on valve rod 4.
The cylinder of electronic control unit 16 join dependencys, when exhaust valve opening or when closing, electronic control unit 16 receives data from telltale 17.These data can be from another control unit, it for example is the drive signal of the central control unit of whole motor, or from the instantaneous angle position data of bent axle, so that according to signal from another signal source 18, the opening and closing number of times of driving in control unit 16, described baseband signal, it for example is the instant engine load data, or, wherein require to drive the outlet valve that departs from operate in standard mode with special type with any possible information on the motor of one of predetermined operator scheme operation.
In the process that valve rod 4 moves between closed position and enable possition, as required, control unit 16 sends signalization by signaling line 19 to outlet valve, and, by the signal of signaling line 20 control units 16 receptions from the valve rod current location of sensor measurement, the current location of described valve rod is the position of valve rod itself, or the position of the element that is connected with valve rod 21 in control valve.
In control valve, electromechanical transducer 22 will be the linear displacement of valve rod 21 from the electrical signal conversion of control unit.In not shown embodiment, control valve is in the position that separates with valve rod 4, therefore has quite long connecting passage between the pressure chamber in control valve port and driver described below.But this structure of separating can make the longitudinal axis of control valve towards other direction, rather than coaxial with the longitudinal axis of valve rod, for example is orientated along substantially horizontal.In addition, owing to have structure separately, transducer 22 can be the device that does not move in the same manner along with valve rod 4, and the substitute is short motion mode, and this short motion mode is converted into the linear motion of the displacement same size that needs with valve rod 4 by amplifying device.For example, the displacement of valve rod can be converted to the four-journey displacement of valve rod in amplifying device, that is, valve rod and valve rod displacement ratio in a longitudinal direction are 1: 4.
By making valve rod 4 displacement along the longitudinal, the displacement of its displacement amount and valve rod is proportional, because valve rod and then valve rod can enter the neutral position of selection, by electromagnetic transducer 22, in any preset time of stem movement, control unit 16 can both make the valve rod braking or quicken.The position of selecting can be predetermined neutral position, or conventional position of calculating, and calculates this position by control unit according to the measured value of the actual motion order of current operator scheme of motor and/or outlet valve.With reference to accompanying drawing 2, wherein described embodiment's plotted curve of a sequence of motion, represent that wherein the downward displacement L of valve rod is the function of time t.At an a, outlet valve is closed fully, and the displacement longitudinally of the valve rod of control valve just begins, therefore driver acts on the valve rod to open active force, make valve rod produce initial motion, make valve rod motion point of arrival b equably continuously, slow in the speed of this position valve rod enough slow, so the closing function power of pneumatic spring enough guide basically valve rod 4 point of arrival c places complete opening maximum position lmax and stop.Valve rod remains on this position then, when making valve rod begin direction travelling backwards towards the initial position when transducer 22, and at a d, the beginning closing movement.When valve rod during near closed position, control unit 16 slows down the speed of valve rod, and up at an e, valve rod enters halted state, leaves in the short distance of closed position at this, has the exhaust clearance of 0.3mm between valve base surface.In this narrow gap, air outwards flows with the velocity of sound, and it produces powerful cooling action, and still, because the gap is very narrow, the flow volume/flow of air is very little.This cooling action can not produce the tangible pressure loss above the piston 23 of combustion chamber.After a period of time of pausing, close fully at a f outlet valve, the above-mentioned dwell time can be undertaken freely adjusting by the empirical value of control unit according to the correlation between current operation mode and the needs cooling degree, perhaps the temperature according to the seat material of actual measurement is that the basis is adjusted, and this is suitable for carrying out work by the temperature transducer that is installed on the fixed valve base.
If under special operating conditions, the fast evacuation cylinder, perhaps need to strengthen the effect that scavenges, make before valve rod 4 speed slow down, control unit 16 can pause one period long period, perhaps replaces to strengthen to slow down from a b ', as shown in phantom in Figure 2.In the corresponding way, dotted line represents that as required closing movement can quicken, for example, because the temporary transient variation of operating conditions makes valve rod accelerate towards the motion of enable possition direction, up at a f ' valve closing.
Fig. 3 represents the closing sequence of valve, and wherein valve rod is at first taken to a f momently " closed position, open again immediately at an e then, enter ventilation position.As mentioned above, this can make any particle of catching between the valve seat of closing be extruded or blow away.Valve seat is not exposed to pretends firmly state, begin to act on the valve disc up to fuel pressure, and the valve Temporarily Closed, therefore on seat material, can not produce big impact, therefore can not form indenture.After the suitable a period of time of pausing, valve rod 4 is displaced to complete closed position, represents with a f .
When motor moved under the partial load effect, the gas volume amount that the motor revolution need be discharged was very little.Therefore, do not need to make valve rod move to full open position.Drive valve rods by control unit 16, so that slow down as early as possible up to stopping, as shown in Figure 4.Valve rod 4 only moves down very little distance, reduces the consumption of liquid stream thus.If the little flow quantity abnormality in conduit 7, control unit receiving alarm signal also can be selected ofer short duration opening movement.
An alternative embodiment of the invention is described below, wherein adopts the label identical to represent to have the component of identical function with front embodiment.
Fig. 5 represents to form with the piston element of driver and control valve the top of whole valve rod 4.Left-half among the figure represents to be in the control valve and the driver of initial position, in this position, exhaust valve closure.Right half part among the figure is represented exhaust valve opening.Valve rod 4 moves up in the wiper seal mode, enters the bottom 25 of the central hole in the actuator housing 24, and described housing 24 has end cap 26 at the top, and end cap 26 has tubular sheath 27 downward extension, that be used for transducer 22.Transducer 22 and valve rod 4 coaxial installations.Transducer 22 can be that Switzerland SULZERELECTRONICS AG produces, trade mark is that Linmot, model are the linear motor of P01-23 * 160, and its maximum stroke reaches 140 millimeters.The magnet component 31 that transducer has the fixed coil parts and movably forms on rod member, in its lower end, the valve rod that is provided with in control valve can not be with respect to parts 31 displacement longitudinally.
In actuator housing, fixing a bottom portion 28 that is used for first pressure chamber 29, the annular wall 30 at valve rod 4 tops protrudes upward in the wiper seal mode, and between the cylindrical outer surface of bottom portion cylindrical form interior surface 37 and tubular sheath 27.Actuator piston comprises the first piston parts 32 and second piston element 34, first piston parts 32 have first open area 33 upwards, described open area 33 is limited by the external diameter and the internal diameter of annular piston parts, and second piston element 34 also has open area 35 upwards.In the initial position, the first piston parts dock with the annular upper surface of second piston element, total open area is corresponding to the zone of annular portion, this annular portion zone is limited by the outer surface of piston element 32 and the outer surface of annular wall 30, the outer surface of described piston element 32 slides with the internal surface of wiper seal mode along chamber, and the outer surface of described annular wall 30 slides with the cylindrical form interior surface 37 of wiper seal mode along bottom portion.
In the process that actuator piston moves downward, first piston parts 32 are located on the step 38 of driver pressure cylinder internal surface, and stop motion, at this moment, have only second piston element to continue motion.At the remainder of opening movement, the open area is reduced to the annular portion zone, and this annular portion zone is limited by the outer surface of piston element 34 and the outer surface of annular wall 30, and the outer surface of described piston element 34 slides along pressure cylinder internal surface 36.
Actuator piston also comprises closes closed region 39, it is corresponding to the annular portion zone, this annular portion zone is limited by the outer surface of valve rod 4 and the outer surface of piston element 34, and the outer surface of described valve rod 4 slides in the wiper seal mode along the bottom 25 of actuator housing.The outer surface of described piston element 34 slides along internal surface 36.This closes closed region and is arranged in second pressure chamber 40.
High-pressure conduit 7 is communicated with the driver chamber at second pressure chamber, 40 places, and imports high-pressure mouth 8 by passage 41.Low-pressure tube 10 is communicated with the cavity of 28 tops, driver chamber middle-end bottom, and passage 42 is communicated with low pressure port 11 and above-mentioned chamber.The valve rod 21 of control valve has intermediate portion and two cylinder-shaped ends of minor diameter, these two cylinder-shaped ends lean on mutually with the internal surface of cylindrical hole in wiper seal mode and the control valve housing 45, shown in the embodiment in the accompanying drawing, control valve housing 45 directly forms on the top of valve rod 4.By short passage 43, the control mouth continues to be communicated with first pressure chamber.In the neutral position of control valve rod, the two end portions of valve rod is just in time blocking high and low pressure port.When valve rod 21 with respect to driven plunger during to bottom offset, high-pressure mouth exposes, and makes fluid enter first pressure chamber, makes actuator piston and valve rod 4 to bottom offset thus, is closed once more up to high-pressure mouth.When valve rod 21 made progress with respect to the actuator piston displacement, low pressure port exposed, and makes fluid flow out first pressure chamber, and actuator piston and valve rod 4 are closed up to low pressure port once more to top offset.Therefore, along with the displacement movement of valve rod 21, the operation of strict controlling and driving device piston.
Owing to adopt this control mode, the opening of actuator piston and pass closed region can be quite big, reserve remaining active force and adjust valve rod 4, and this can guarantee to adjust quickly and accurately motion.Owing to allow to have remaining active force, the size of piston area can be calculated according to the minimum adjustable seamless power in the high-pressure conduit 7, so that the variation of pressure can only cause remaining the active force increase in conduit.
When driver was carried out the adjustment motion, fluid flowed and the cooling driver.In the embodiment shown in fig. 5, control valve and actuator piston form one, its advantage is the length minimum from the control mouth to the passage 43 of chamber 29, so the control connection between the motion of valve rod adjustment and actuator piston directly accurately and reliably, and the output loss is minimum.
Discharge route 44 can remain on the space cleaning of first piston parts 32 belows, gets rid of the fluid of any seepage.In the embodiment shown in fig. 5, do not need the pneumatic spring of setting on valve rod 4 to use.If the employing pneumatic spring can omit first and close closed region 39, in addition, when determining this regional size, should consider that pneumatic spring also has closing function power.
Above describedly be used to keep outlet valve stage, cooling channel position and extruding in the end, the method that blows any particulate open also can be used to be connected other driver, for example, cam controlling and driving device, still, embodiment's particularly suitable recited above, this is because it has the function of accurate adjustment.
Can also embodiment shown in Figure 5 be made amendment.For example, actuator piston and valve rod 4 separated make and separate, and with the extension of actuator piston as valve rod 4, can be by bolt connection piece, threaded connector or pin link, this link is inserted in the cross-perforating of two parts, perhaps by other mechanical fastening system that is provided with along axial direction.For actuator piston itself, the control valve housing can also form element separately, is inserted into and is fixed in the hole of actuator piston.This fixed structure can be made by the outer surface of conical shell, and the hole of piston has corresponding conical surface, and it contacts with housing pressure, and perhaps parts can shrink fit or with being threaded togather.