CN100432415C - Common-rail injector - Google Patents
Common-rail injector Download PDFInfo
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- CN100432415C CN100432415C CNB2005100818938A CN200510081893A CN100432415C CN 100432415 C CN100432415 C CN 100432415C CN B2005100818938 A CNB2005100818938 A CN B2005100818938A CN 200510081893 A CN200510081893 A CN 200510081893A CN 100432415 C CN100432415 C CN 100432415C
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Abstract
The present invention provides a common rail injector (1) for injecting fuel through a high-pressure channel (12) includes a control chamber (4), a control valve (102), and a drive unit (101). The control chamber (4) applies pressure to a nozzle needle (5). The control valve (102) switches communication of the control chamber (4) between the high-pressure channel (12) and a low-pressure channel (13). The drive unit (101) selectively sets a valve element (2) of the control valve (102) on a low-pressure side seat (22) or a high-pressure side seat (23). The drive unit (101) has an actuator (6) and a slide pin member (3). The slide pin member (3) slides inside a slide hole (31) to transmit a force to the valve element (2). A diameter of the low-pressure side seat (22) is less than or equal to a diameter of the high-pressure side seat (23). The pressure in the control chamber (4) is exerted as an assistance force, so that a high-pressure side seat closing load becomes less than or equal to a low-pressure side seat opening load.
Description
Technical field
The present invention relates to a kind of common-rail injector that is used for diesel engine, more specifically, relate to a kind of oil sprayer of controlling the control room pressure that moves up and down nozzle needle with three-way valve.
Background technique
In diesel engine, common rail type fuel injection system is known, and wherein shared one of each cylinder is total to rail to accumulate fuel under high pressure.Fuel under high pressure is transported to from an oil transfer pump and has altogether the rail, and is controlled as a predetermined pressure.The oil sprayer that drives each cylinder in predetermined timing comes burner oil then.A common-rail injector has one usually and is used for applying the control room of a pressure and the control valve of this control room pressure of control to nozzle needle on the valve closing direction.This oil sprayer is designed to come drive control valve by an actuator, to increase and to reduce the pressure in control room.
For control valve, be suitable for adopting a three-way valve structure, be connected with high-pressure channel or low-pressure channel optionally to make the control room.The valve planning of this three-way valve is in valve chamber, and this valve chamber has the low voltage side valve seat and the high pressure side valve seat that leads to high-pressure channel that lead to low-pressure channel.This valve element moves with the switching valve seat at two valve base chambers and puts.For this three-way valve structure, can when oil spout, interrupt when the valve element is positioned on the valve seat of high pressure side and being communicated with of high-pressure channel, thereby prevent that fuel under high pressure from flowing out from valve chamber.Such as, an available piezoelectric actuator is used as actuator.When energising, this piezoelectric actuator extends, and with from low voltage side valve seat relief valve element, then it is placed on the valve seat of high pressure side.Because piezoelectric actuator has good responsiveness, thereby can realize the control of oil spout accurately.
For example, in the open text No.2000-130614 of (1) Japan Patent, the open text No.2002-227747 of (2) Japan Patent, the open text No.2001-41125 of (3) Japan Patent, (4) Japanese PCT open text No.2001-500218 of country and the open text No.2001-140726 of (5) Japan Patent the control valve with three-way valve structure is disclosed.Listed preceding four patent documentations comprise a throttle valve that places low voltage side valve seat downstream.This structure is particularly conducive to the opening speed that suppresses nozzle, thereby improves the controllability of fuel injection quantity.
Equally, in order to operate common rail type fuel injection system effectively, need reduce fuel leak as much as possible.Yet listed preceding two patent documentations have adopted a kind of equilibrated valve, and this valve produces leakage through regular meeting by its sliding parts the time.In this case, pump just need carry out extra work, and this leakage has increased fuel temperature and made the fuel variation.The control valve of the 3rd listed patent documentation has a spherical valve member, and in order to adapt to this structure, its high pressure side valve base element and low voltage side valve base element are configured to parts separately.In this case, owing to two position component switchings also can be leaked.This discusses in listed second piece and the 5th piece of patent documentation to some extent.Therefore, when amount of boost is very little, be difficult to use.
The 5th piece of listed patent documentation proposed to be provided with a plurality of valve elements that can relatively move, even if also can carry out correct operation when switching in the position.Yet this structure is very complicated.In addition, in order to improve the controllability of fuel injection quantity, need to improve the closing velocity of nozzle.Usually, the open area that can increase the high pressure side valve seat improves the closing velocity of nozzle.Yet,, so increase the open area of high pressure side valve seat closed driving force is strengthened, thereby have the problem that reduces energy efficiency because piezoelectric actuator has amount of movement and the characteristic that the power that is produced is inversely proportional to.
Summary of the invention
One embodiment of the present of invention have reduced the necessary driving force of closed oil sprayer high pressure side valve seat, this oil sprayer is to be used in the common rail type fuel injection system of a diesel engine or similar device, and this embodiment can reduce fuel leak in the control valve by a simple topology layout, reduce the nozzle opening speed or increase the nozzle closing velocity, thereby increase energy efficiency, and the High Accuracy Control of realization emitted dose.
In the content, oil sprayer comprises the control valve of three-way valve structure in one aspect of the invention, is used to increase or reduce the control room pressure that produces the nozzle back pressure.Its driver element is made up of actuator and sliding pin element.This sliding pin element has a pin-shaped end portion, and the valve element of the described control valve that this end is interior with being contained in valve chamber contacts.This sliding pin element can slide in a sliding eye according to the displacement of described actuator, thereby optionally is shelved on low voltage side valve seat or the high pressure side valve seat.One between described sliding pin sliding parts and described low voltage side valve seat the space around described sliding pin end partly link to each other by throttle valve with described low-pressure channel.When the diameter of described low voltage side valve seat is less than or equal to described high pressure side valve-seat diameter, can be used as an auxiliary force with the pressure in the described control room that described valve chamber is connected, thereby make the unlatching load that load is less than or equal to the low voltage side valve seat of closing of high pressure side valve seat.
According to aforementioned structure, be located at sliding pin end throttle valve part on every side and can when the low voltage side valve seat is opened, reduce the nozzle opening speed.In addition, the pressure in control room can be applied on the closing direction of high pressure side valve seat, thereby reduces the driving force of closed high side valve seat.Therefore, the diameter that can increase the high pressure side valve seat by a simple structural design to be obtaining higher valve closing velocity, and improves and spray controllability and energy efficiency.
Content according to a further aspect in the invention, following relation is arranged between the slip diameter of sliding eye and low voltage side valve seat and the high pressure side valve-seat diameter: described slip diameter is less than or equal to the diameter of described low voltage side valve seat, and the diameter of described low voltage side valve seat is less than or equal to the diameter of described high pressure side valve seat.The diameter that can reduce to slide reduces to open closed necessary driving force, particularly the required power of closed high side valve seat.
Content according to a further aspect in the invention, one between described sliding pin sliding parts and described low voltage side valve seat the space around described sliding pin end partly link to each other by a throttle valve with described low-pressure channel.In addition, following relation is arranged between the slip diameter of sliding parts and the high pressure side valve-seat diameter: described slip diameter is less than or equal to the diameter of described high pressure side valve seat.This makes the described control room internal pressure that is connected with described valve chamber can be used as an auxiliary force.
According to aforementioned structure, be located at sliding pin end throttle valve part on every side and can when the low voltage side valve seat is opened, reduce the nozzle opening speed.In addition, the pressure in control room can be applied on the closing direction of high pressure side valve seat, thereby reduces the driving force of closed high side valve seat.In addition, can reduce to slide diameter to reduce the necessary driving force of closed high side valve seat.Therefore, the diameter that can increase the high pressure side valve seat by a simple structural design to be obtaining higher valve closing velocity, and improves and spray controllability and energy efficiency.
Content according to a further aspect in the invention, the pressure in the described control room that is communicated with described valve chamber can be used as an auxiliary force, thereby makes the unlatching load that load is equal to or less than the low voltage side valve seat of closing of high pressure side valve seat.
Control room pressure can suitably be adjusted into and make the high pressure side valve seat close load to be less than or equal to the low voltage side valve seat and to open load, thereby further improves energy efficiency.
Content according to a further aspect in the invention, actuator is a piezoelectric actuator.Because one embodiment of the present of invention comprise piezoelectric actuator, it has the relation that the power that produced reduces with the increase of displacement, thereby can effectively utilize its characteristic.
Content according to a further aspect in the invention can make nozzle needle control of turning chamber pressure be set as to be at least 50% of fuel-supplying pressure under maximum load or the pressure maximum.This makes the high pressure side valve seat close load and opens load less than the low voltage side valve seat, thereby realizes effective control of emitted dose.
Content according to a further aspect in the invention, sliding pin and valve element are separated to make independent element.This is convenient to the processing of valve seat part.
Content according to a further aspect in the invention, the two ends shape of described sliding pin is similar to a pin, and its diameter is less than the slip diameter.This can get rid of the fault that causes owing to assembly defect.
Content according to a further aspect in the invention, sliding pin can be made as a cylindrical pin with constant diameter.In this case, the sliding eye end of leading to the low voltage side valve seat has an expansion that diameter is bigger, and the end of described sliding pin is positioned at it, and described throttle valve partly is formed to this expansion opening.This has simplified the structure of sliding pin and has been easy to processing.
Content according to a further aspect in the invention, the valve element has a roughly hemispheric shape.When the surface of contact that withstands described sliding pin is processed into a curvature greater than the sphere of ball curvature, can provide the effect of avoiding unsmooth contact and discharging Hertz stress.
Content according to a further aspect in the invention, at least one slip surface of sliding pin is made by a superhard material or stupalith.This can improve stability and reduce or prevent wearing and tearing.
Content according to a further aspect in the invention, sliding pin is made by the superhard material that a Young's modulus is higher than metal.This can reach the effect that reduces or prevent deformation loss.
Content according to a further aspect in the invention is provided with a valve spring at the upstream side of described high pressure side valve seat, with to the described valve element of low voltage side valve seat bias voltage.Thereby can reduce the valve chamber volume and obtain higher speed of response.
Content according to a further aspect in the invention, each independent assembly is designed to satisfy following representation:
Control room pressure ratio when wherein kpo is the nozzle unlatching, Ds is the diameter of the nozzle valve seat at nozzle needle place, Dc is the slip diameter in control room, Fk is that nozzle is provided with load, Pc is that when Pc=Pcmax, Pc is maximum supply pressure from the fuel-supplying pressure that is total to rail.
Therefore, can obtain the aforementioned effect that the high pressure side valve seat is opened load and reduced the driving force of closed high side valve seat that reduces easily.
Description of drawings
Constitute hereinafter detailed description, claims and the accompanying drawing of the application's part by research, be appreciated that other features and advantages of the present invention, such as the function of operating method and relevant portion etc.In the accompanying drawings:
Fig. 1 is the sectional drawing according to the oil sprayer of first embodiment of the invention;
Fig. 2 A is the detailed cross sectional view of the low voltage side valve seat according to first embodiment of the invention when being in opening state;
Fig. 2 B is the detailed cross sectional view of the high pressure side valve seat according to first embodiment of the invention when being in closed state;
Fig. 3 is the detailed cross sectional view according to an optional embodiment of the sliding pin element of first embodiment of the invention;
Fig. 4 is a chart, represented control chamber pressure when opening according to the first embodiment of the invention nozzle than and the low voltage side valve seat open load and high pressure side valve seat and close relation between the load;
Fig. 5 A is a chart, expression according to one embodiment of the invention when the situation of opening of valves speed during greater than the valve closing velocity;
Fig. 5 B is a chart, expression according to one embodiment of the invention when the situation of opening of valves speed during less than the valve closing velocity;
Fig. 6 is the part sectioned view according to the oil sprayer of second embodiment of the invention;
Fig. 7 is the part sectioned view according to the oil sprayer of third embodiment of the invention;
Fig. 8 is the detailed cross sectional view of oil sprayer valve element shown in Figure 7.
Embodiment
Below, the present invention will be described with reference to the accompanying drawings.Fig. 1 is the sectional drawing according to first embodiment's oil sprayer 1, and it is described as the example on the common rail type fuel injection system that first embodiment of the invention is applied in diesel engine.This oil sprayer 1 is arranged (one of them only is shown) here corresponding to each cylinder of motor, and receives supply of fuel the rail altogether from one.The fuel of carrying by a high pressure supply pump is accumulated in the common rail with a predetermined high pressure corresponding to jet pressure.
In Fig. 1, upper half part of oil sprayer 1 is a driver element 101 that has a piezoelectric actuator 6.Drive nozzle unit 103 with a control valve unit 102 that has the three-way valve structure, this nozzle unit has one and is used for the nozzle needle 5 that fuel sprays.This oil sprayer 1 is connected (not shown) on the not shown combustion chamber wall surface.On the inboard of the casing member H1 to H4 that holds aforementioned each unit 101 to 103 assembly, be provided with for example passage of high-pressure channel 12 and low-pressure channel 13, this high-pressure channel 12 rail (not shown) together is connected by a fuel inlet 11, and this low-pressure channel 13 is connected with a fuel tank (not shown) by a fuel outlet 14.This casing member H1 to H4 comes fastening and oily close fixing by a retainer H5.
In nozzle unit 103, nozzle needle 5 has a flange 51 on its periphery, and this nozzle needle 5 slides and remains on the tubular portion 42 on the casing member H1 top.The space of casing member H4 inboard has formed an accumulator 52, the fuel under high pressure that it obtains supplying from common rail by high-pressure channel 12, high-pressure channel 12 wall upper shed thereon.A bag portion (sack part) 53 is arranged on the bottom of casing member H4.The wall that constitutes this bag portion 53 is provided with the spray-hole 54 that passes wall.
When nozzle needle 5 was in bottom position, its tapered distal end was shelved on the nozzle valve seat 55 on accumulator 52 and bag portion 53 interfaces, thus closed this bag portion 53, interruption supply of fuel of 54 from accumulator 52 to spray-hole.When nozzle needle 5 raises and leaves nozzle valve seat 55 with opened pocket portion 53, the fuel ejection.
The space of being determined by the bottom of the internal face of the top of nozzle needle 5, tubular portion 42 and casing member H3 has formed the control room 4 of a control nozzle back pressure.Fuel or control oil enter control room 4 from the valve chamber 21 and the passage 25 of high-pressure channel by control valve unit 102, thereby produce the back pressure of nozzle needle 5.This back pressure acts on downwards on the nozzle needle 5, and along spring 56 bias voltage nozzle needle 5 on closing direction, its medi-spring 56 is fixed between the bottom of flange 51 and tubular portion 42.Simultaneously, the fuel under high pressure in the accumulator 52 upwards acts on the conical surface of nozzle needle 5 ends, bias voltage nozzle needle 5 on opening direction.
The control valve unit 102 of this three-way valve structure has valve chamber 21 and valve element 2, and valve chamber always is connected with the control room 4 of nozzle unit 103 by a communication passage 41, and it is spherical that valve element 2 is generally, and be contained in the valve chamber 21.The open top of valve chamber 21 is provided with low voltage side valve seat 22, and bottom opening is provided with high pressure side valve seat 23, thereby the valve element can optionally be shelved on one of these valve seats 22,23.A throttle valve part 32 that is used to be provided with the nozzle opening speed is arranged on the downstream side of low voltage side valve seat 22, and is connected with low-pressure channel 13 by passage 33,34.Passage 25 on the upstream side of high pressure side valve seat 23 is connected with high-pressure channel 12.Valve element 2 is activated the driving of unit 101 pressure and moves up and down, thus the valve seat position of changeable valve element 2.Valve chamber 21 is connected with high-pressure channel 12 or low-pressure channel 13 thus, thus the pressure in the control room 4 that increase or reduction link to each other with valve chamber 21, and it is the back pressure that acts on the nozzle needle 5.
On the end of the passage 25 of valve chamber 21 sides a valve spring 24 is set, it is bias valve element 2 upwards in the accompanying drawings.When the high voltage supply pump begins to pressurize during at engine start, for pressure charging valve element 2 fast must be pressed towards low voltage side valve seat 22.If valve spring 24 is arranged on the inboard of valve chamber 21 for this reason, the volume in the volume of valve chamber 21 and control room 4 will increase, and speed of response descends.Thereby, in the present embodiment valve spring 24 is arranged on the upstream side of high pressure side valve seat 22, but should be appreciated that the present invention is not restricted to this structural configuration.
Hydraulic Power Transmission System 61 comprises first piston 62, second piston 64 and oil seal chamber 63, and the first piston and second piston have same diameter and all slide and be arranged in the tubular holders element 15, and oil seal chamber 63 is arranged between the two-piston and hydraulic oil is housed.First piston 62 has a large diameter top, stretches out the bottom of contact piezoelectric actuator 6 from sleeve 15 tops.Piezoelectric spring 65 is arranged between major diameter top and sleeve 15 tops, and it applies a certain size initial load for piezoelectric actuator 16 by first piston 62.Therefore, first piston 62 can keep together moving up and down with the contact condition of piezoelectric actuator 6 and along with the flexible of piezoelectric actuator 6.
In oil seal chamber 63, be provided with a valve spring 66, its biased downward second piston 64.The bottom of second piston 64 contacts with sliding pin element 3.Sliding pin 3 is arranged to and can slides in sliding eye 31, and this sliding eye 31 is positioned at casing member H2.Valve element 2 in the bottom of sliding pin and the valve chamber 21 contacts.It is an interior vertical hole of casing member H1 that sliding eye 31 is set as, and interconnects with valve chamber 21.Therefore, when piezoelectric actuator 6 elongation with when pressing down first piston 62, this pressure is converted into the hydraulic coupling in the oil seal chamber 63, and passes to second piston 64.Second piston 64 comes actuating valve element 2 by sliding pin element 3.The shape of sliding pin 3 is similar to a pin, and makes its two ends diameter less than its stage casing diameter.One of its two ends contact with the bottom of second piston 64, and the other end contacts with the top of valve element 2.
Shown in Fig. 2 A, around the 3a of pin-shaped end portion of sliding eye 31 internal valve elements 2 sides, between the sliding parts of sliding pin 3 and the low voltage side valve seat 22, formed an annular space.Throttle valve part 32 in sliding eye 31 sidewall upper sheds towards this annular space.In one embodiment, 3 of sliding pins have small diameter portion on the 3a of end.This can reduce the diameter (a given constant slip diameter) of low voltage side valve seat, and the driving force that reduces to open the low voltage side valve seat.This valve element 2 is hemisphere roughly, has a plane and a sphere, is arranged in the valve chamber 21, and sphere upwards in the drawings.Valve element 2 contact with sliding pin 3 surface of contact be machined and be sphere, its curvature is greater than the original curvature of valve element 2.This is for fear of contacting with the unsmooth of sliding pin 3, and discharges Hertz stress.In valve chamber 21 sliding eye 31 openings towards top, be provided with the low voltage side valve seat 22 of conical surface shape, this conical surface contacts with the sphere of valve element 2.The bottom that has passage 25 in the valve chamber is provided with high pressure side valve seat 23, and it contacts for horizontal plane and with the plane of valve element 2.
As indicated above, when one of valve seat part is made as planar valve seat, can reduce the possibility of valve element 2 and low voltage side valve seat or the failure in place of high pressure side valve seat, change even if constitute the casing member H2 and the H3 position of valve chamber 2.Therefore can reduce or prevent seepage, and be convenient to processing.In addition, consider that impurity adheres to (biting) on valve seat part, smooth sphere-conical surface valve seat can be easier to adhere to than the planar valve seat that the angle is arranged.If the high pressure side valve seat part is adsorbed impurity and caused failure in place, then can reduce emitted dose.If low voltage side valve seat absorption impurity and the delay that produces the valve closure, the nozzle closing time that has postponed on the other hand can cause the increase of emitted dose.For fear of this situation, the shape of low voltage side valve seat need be set as a smooth sphere-coned face.
For fear of wearing and tearing and guarantee slidably property, preferably this sliding pin 3 is set as at least its slidingsurface and makes by superhard material or pottery.Yet, be to be understood that also and can adopt other alternative materials.In addition, for fear of deformation loss, the preferred element that is similar to superhard material that adopts with high yang type modulus.Yet, should understand also and can adopt other alternative materials.In addition, although sliding pin 3 and valve element 2 are made into independent element in the present embodiment, it also can be combined into an integral piece in optional embodiment.Make the low voltage side valve seat part that independent element helps processing valve element 2.As indicated above, in order to form annular space in sliding eye 31, sliding pin 3 can only be made the pin shape of minor diameter on a close side of valve element 2.Yet, preferably identical pin shape is all made at two ends in the present embodiment.Can eliminate the difference between bottom and the top like this, thereby be convenient to assembling.
In addition, as shown in Figure 3, sliding pin 3 can be a cylindrical pin that all has same diameter on its total length.In this case, between sliding parts and low voltage side valve seat 22, sliding eye 31 is made of an expansion 31a with valve element 2 contacted ends, and its diameter is greater than the diameter of sliding parts, thereby throttling valve portion 32 is arranged on this expansion.This has simplified the shape of sliding pin 3 and has been convenient to processing.This is by unmanageable for example advantageous particularly when superhard material is made at sliding pin 3.
In the present invention, the relation between the valve-seat diameter of low voltage side valve seat 22 and high pressure side valve seat 23 is to make the diameter of low voltage side valve seat 22 be less than or equal to the diameter of high pressure side valve seat 23, and preferably with the low voltage side valve-seat diameter less than the high pressure side valve-seat diameter.When the opening area of high pressure side valve seat during, can when the rapid closing nozzle, increase the pressure in the control room, thereby increase the nozzle closing velocity greater than the opening area of low voltage side valve seat.Therefore, when valve element 2 is made sphere, the center that the seat plane on the valve element 2 will be set up near sphere.If spherical center is departed from this plane, the low voltage side valve-seat diameter is just less than required high pressure side valve-seat diameter, so as the conical surface of the casing member H2 of low voltage side valve seat 22 just near 180 °, thereby destroy stability in place.Relation between the valve-seat diameter of the slip diameter of sliding pin 3 and low voltage side valve seat 22 and high pressure side valve seat 23 is to make the slip diameter be less than or equal to the low voltage side valve-seat diameter, and the low voltage side valve-seat diameter is less than or equal to the high pressure side valve-seat diameter.This slip diameter be can reduce and unlatching closure or the particularly necessary driving force of closed high side valve seat reduced.
This low voltage side valve seat 22 preferably has a less valve-seat diameter, thereby can reduce the unlatching load of low voltage side valve seat.When the low voltage side valve seat was closed, shown in Fig. 2 A, the inside of valve chamber 21 was in high pressure (the supply pressure Pc of rail altogether) and this supply pressure Pc upwards acts on the unlatching zone of low voltage side valve seat 22.Therefore, the valve-seat diameter that reduces low voltage side valve seat 22 can reduce the unlatching load of low voltage side valve seat, thereby reduces to open necessary driving force.
In addition, for the power that guarantees that the bigger high pressure side valve seat of closed diameter 23 is required, when closed high side valve seat 23, can utilize fuel pressure in the valve chamber 21 as an aux. pressure.This can make the closed driving force of high pressure side valve seat multiply by the value of supply pressure less than high pressure side valve seat opening area.Shown in Fig. 2 B, for the topology layout that throttle valve part 32 is positioned at low voltage side valve seat 22 downstreams, when opening the low voltage side valve seat, the pressure of valve chamber 21 is the pressure that the pressure in the control room 4 is higher than low-pressure channel 13.Then, with this pressure keep high as far as possible, can open nozzle needle 5 simultaneously, close load thereby can reduce the high pressure side valve seat as much as possible.The control chamber pressure is than kpo (pressure when nozzle needle 5 can be opened in the control room 4 and the ratio of supply pressure) when opening according to nozzle, and the pressure of valve chamber 21 is represented as kpoPc.Then, from supply pressure Pc, deduct this pressure kpoPc and can obtain pressure P c (1-kpo), act on its direction that makes progress in the drawings on the unlatching zone of high pressure side valve seat and low voltage side valve seat.
Especially, when normal the use, nozzle needle 5 can not be elevated to contact blocks fully, and this block promptly is the top in control room.Determine various settings, thereby make the pressure in control room 4 can not fall or be lower than half of supply pressure Pc that supply pressure Pc is more than or equal to half of maximum supply pressure Pcmax at least within the specific limits.Control room pressure ratio kpo is suitable for being set as and makes high pressure side valve seat unlatching load be less than or equal to low voltage side valve seat unlatching load.For an exemplary embodiments, Fig. 4 is illustrated in sliding pin 3
And maximum supply pressure is under the 200Mpa situation, and the control chamber pressure is closed relation between the load than kpo and low voltage side valve seat unlatching load and high pressure side valve seat when nozzle is opened.The represented control room pressure ratio kpo of following as can be seen from the figure representation is high more, it is just more little that the high pressure side valve seat is closed load, and control room pressure ratio kpo is about at 0.5 o'clock or can make the high pressure side valve seat close load when higher opens load less than the low voltage side valve seat.
[representation 3]
| Kpo: the control room pressure ratio Ds when nozzle is opened: nozzle valve-seat diameter Dc: control room slip diameter Fk: nozzle is provided with load p c: supply pressure |
Usually, the output characteristics of piezoelectric actuator 6 is that the power that increase produced along with displacement bimorph reduces.Because near the power that is produced high pressure side valve seat 23 when displacement is big reduces, thereby will increase the driving energy for the power that will guarantee the high pressure side valve seat 23 that closed valve-seat diameter is bigger.When adopting when increasing the piezoelectric actuator 6 that the power that produced diminishes with displacement, the present invention can utilize fuel pressures in the valve chamber 21 as the design of aux. pressure, thereby can reduce the load of closing of high pressure side valve seat.Particularly, by determining that nozzle valve-seat diameter, nozzle slip diameter and nozzle valve seat load satisfy aforementioned representation.
Below, the oil sprayer 1 with aforementioned structure is described.State when the piezoelectric actuator discharge of Fig. 2 A presentation graphs 1 is shunk.Valve element 2 is positioned on its tip position with closed low side valve seat 22, thereby interrupts being communicated with of throttle valve part 32 and passage 33, and causes the interruption that is communicated with between low-pressure channel 13 and the valve element 2.Valve chamber 2 flows into and is in high pressure conditions owing to fuel passes passage 25 and high pressure side valve seat 23 from high-pressure channel 12.At this, the control room 4 that is connected with valve element 2 by communication passage 41 becomes high pressure.The biasing force of the pressure in this control room 4 and spring 56 is shelved on nozzle needle on the nozzle valve seat 55, thereby does not have the fuel ejection.
When piezoelectric actuator 6 during from the energising of this state, these piezoelectric actuator 6 elongations.Thereby first piston 62 moves down and compressed oil closed chamber 63 in hydraulic oil (being light oil here).When the pressure of this hydraulic oil promoted second piston and sliding pin 3 downwards and promotes valve element 2 downwards, valve element 2 left low voltage side valve seat 22 and more moves down to be shelved on the high pressure side valve seat 23.Therefore, control room 4 is connected with low-pressure channel 13 by valve chamber 21, low voltage side valve seat 22, throttle valve part 32 and passage 33.When the pressure in control room 4 descends and the downward bias pressure of nozzle needle 5 when dropping to the biasing force that is lower than upwards, nozzle needle 5 is lifted off a seat and is begun fuel and spray.Here, because control room 4 has throttle valve part 32 in the first time on valve seat 22 the downstream, thereby pressure is steadily descended and reduce the nozzle opening speed.
In addition, the pressure kpoPc of valve chamber 21 can be used as the auxiliary force on closed high side valve seat 23 directions.This makes the high pressure side valve seat close load and is less than or equal to low voltage side valve seat unlatching load, thereby makes the reduction of the closed driving force of high pressure side valve seat.Therefore, can effectively utilize the output characteristics of piezoelectric actuator 6.
When piezoelectric actuator 6 discharged contraction once more, first piston moved up.The pressure that reduces oil seal chamber 63 is to discharge to the power that presses down valve element 2.Therefore, valve element 2 is shelved on the low voltage side valve seat 22 to cut off being interconnected of control room 4 and low-pressure channel 13.Cause the pressure in control room 4 to rise once more in the passage 25 owing to fuel under high pressure flows into, and needle-valve 3 is shelved on the valve seat and end injection.Here, because the low voltage side valve-seat diameter is less than or equal to the high pressure side valve-seat diameter, so the pressure in control room 4 rises to obtain a higher nozzle closing velocity rapidly.
Fig. 5 is the graph of a relation of the controllability of expression nozzle opening speed and nozzle closing velocity and emitted dose.Fig. 5 A represents the situation of nozzle opening speed greater than the nozzle closing velocity, and Fig. 5 B represents the situation of nozzle opening speed less than the nozzle closing velocity.In order to obtain identical rectangular jet level, the summation of nozzle opening speed and nozzle closing velocity should be constant.In Fig. 5 A and Fig. 5 B, if change to B2 between at B1 the instruction time of injection end, this variation is because the variation of driving pulse concluding time causes, comprises that noise effect, piezoelectricity shrink or analogue, and the injection end time just changes between C1 and C2 so.Here as can be seen when the lower and nozzle closing velocity of nozzle opening speed is higher, shown in Fig. 5 B, the variation of injection end time and the variation of emitted dose will reduce along with the raising of emitted dose controllability.
Fig. 6 shows the second embodiment of the present invention, comprises another configuration example of the Hydraulic Power Transmission System of piezo-electric drive units 101.The basic structure of oil sprayer 1 is all identical with aforementioned first embodiment with fundamental operation.So omit explanation to it.As shown in Figure 6, according to the present invention, tubular and first piston 62 that have a closed top end can slide in tubular sleeve.Second piston, 64 slips that have than minor diameter are arranged in the first piston 62.The oil seal chamber 63 that is filled with hydraulic oil is located in the space between the first piston 62 and second piston 64.First piston 62 is by piezoelectric springs 66 bias voltage upwards that is placed on below the first piston 62, and a sliding pin 3 is placed on the position of touching with second piston, 64 bottom connections, and stretch out downwards from the pipe inboard of first piston 62 bottom of second piston 64.An one-way valve 67 is set on the upper wall surface of first piston 62, is communicated with thereby between oil seal chamber 63 and low-pressure section, form.When the pressure that causes oil seal chamber 63 owing to leakage descended, fuel pressed ball valve downwards and flows into from low-pressure section.Thereby can fill up the oil seal chamber again.
Present embodiment also can reach the identical effect with aforementioned each embodiment.In addition, in the present embodiment, second piston 64 is contained in the first piston 62.This structure has reduced the axial length of Hydraulic Power Transmission System 61.Thereby whole oil sprayer becomes compacter.
Fig. 7 and 8 the expression third embodiment of the present invention, perhaps another structure examples of control valve unit 102.The basic structure of oil sprayer 1 is all identical with aforementioned first embodiment with fundamental operation.So omit explanation to it.Shown in Fig. 7 and 8, according to the present invention, the shape of valve element 2 is similar to mushroom, and it is made up of a lower half portion hemispheric upper half part and a cylindricality, that external diameter is less roughly.Sliding pin 3 is cylindrical pins, and it has identical diameter on total length.The end of the sliding eye 31 at this place, pin end is made into an expansion 3a, and its diameter is greater than the slip diameter, and throttle valve part 32 opening thereon.A valve spring 24 is arranged in the valve element 21, and is bearing in being similar between upper half part that flange stretches out of the bottom of valve element 21 and valve element.
In this embodiment's this configuration, it is smaller that the high pressure side valve-seat diameter can be done, because valve spring 24 is not arranged in the upstream passageway of high pressure side valve seat 23.This makes can reduce closed high side valve seat 23 necessary driving forces.In addition, and previous embodiments, the slip diameter is less than or equal to the high pressure side valve-seat diameter, thus the load of closing of high pressure side valve seat 23 can further be reduced, thus improve energy efficiency.In addition, in the present embodiment, the high pressure side valve-seat diameter is less than or equal to the low voltage side valve-seat diameter.In the aforementioned embodiment, will increase the high pressure side valve-seat diameter in order to increase the nozzle closing velocity, yet this not restrictive.The same with present embodiment, the high pressure side valve seat can be done is less than or equal to the low voltage side valve seat, thereby can effectively utilize the output characteristics of piezoelectric actuator 6, and it produces higher power near low voltage side valve seat 22.
In addition, as shown in Figure 7, according to present embodiment, the communication passage 41 between control room 4 and the valve chamber 21 can be used as a throttle valve, and its opening area is less than the opening area of low voltage side valve seat 22.This can suppress the variation in pressure in control room 4, thereby suppresses vibration when opening nozzle needle 5.
And previous embodiments, when being used as actuator with piezoelectric actuator 6, displacement is minimum.Like this, can adopt to have the Hydraulic Power Transmission System 61 that large diameter first piston 62 and minor diameter second piston 64 combine, it can make transmission of power more efficient.
Can use any device as actuator, as long as it can produce displacement when energising.Piezoelectric actuator except adopting in aforementioned each embodiment also can use magnetostrictor or similar device.
Claims (13)
1. a common-rail injector (1) is used for by high-pressure channel (12) comprising from rail burner oil altogether:
Control room (4) is used for exerting pressure to nozzle needle (5) on the valve closing direction;
Control valve (102), it has the connected sum that the three-way valve structure is used to switch between described control room (4) and described high-pressure channel (12) and the low-pressure channel (13) and interrupts, thereby increases or reduce the pressure of described control room (4); With
Drive single (101), be used to drive the valve element (2) of described control valve (102), optionally valve element (2) is arranged on the low voltage side valve seat (22) that is connected with described low-pressure channel (13), or be arranged on the high pressure side valve seat (23) that is connected with described high-pressure channel (12), wherein
Described driver element (101) has the actuator (6) and the sliding pin element (3) of generation displacement when energising, this pin element slides in sliding eye (31) and comes transmission of drive force with the displacement according to described actuator (6), described sliding pin element (3) has pin-shaped end portion (3a), the described valve element (2) of the described control valve (102) that this end is interior with being contained in valve chamber (21) contacts
Be arranged between the sliding parts of described sliding pin element and the described low voltage side valve seat around the space of described pin-shaped end portion, this space links to each other with described low-pressure channel (13) by a throttle valve part (32),
The diameter of described low voltage side valve seat (22) be less than or equal to described high pressure side valve seat (23) diameter and
With described control room (4) that described valve chamber (21) is connected in pressure as an auxiliary force, thereby make the unlatching load that load is less than or equal to the low voltage side valve seat of closing of high pressure side valve seat.
2. according to the common-rail injector (1) of claim 1, it is characterized in that: the slip diameter of described sliding eye (31) is less than or equal to the diameter of described low voltage side valve seat (22).
3. a common-rail injector (1) is used for by high-pressure channel (12) comprising from rail burner oil altogether:
Control room (4) is used for exerting pressure to a nozzle needle (5) on the valve closing direction;
Control valve (102), it has the connected sum that the three-way valve structure is used to switch between described control room (4) and described high-pressure channel (12) and the low-pressure channel (13) and interrupts, thereby increases or reduce the pressure of described control room (4); With
Driver element (101), be used to drive the valve element (2) of described control valve (102), optionally valve element (2) is arranged on the low voltage side valve seat (22) that is connected with described low-pressure channel (13), or be arranged on the high pressure side valve seat (23) that is connected with described high-pressure channel (12), wherein
Described driver element (101) has the actuator (6) and the sliding pin element (3) of generation displacement when energising, this pin element slides in sliding eye (31) and comes transmission of drive force with the displacement according to described actuator (6), described sliding pin element (3) has pin-shaped end portion (3a), the valve element (2) of the described control valve (102) that this end is interior with being contained in valve chamber (21) contacts
Be arranged on the space that centers on described pin-shaped end portion (3a) between described sliding pin element (3) sliding parts and the described low voltage side valve seat (22), this space links to each other with described low-pressure channel (13) by throttle valve part (32),
The diameter of the described sliding parts of described sliding pin element (3) is less than or equal to the diameter of described high pressure side valve seat (23), and
With described control room (4) that described valve chamber (21) is connected in pressure as an auxiliary force.
4. according to the common-rail injector (1) of claim 3, it is characterized in that: the high pressure side valve seat close the unlatching load that load is equal to or less than the low voltage side valve seat.
5. according to the common-rail injector (1) of claim 3, it is characterized in that: described actuator (6) is a piezoelectric actuator.
6. according to the common-rail injector (1) of claim 3, it is characterized in that: when fuel-supplying pressure was maximum fuel pressure from rail altogether, can make the pressure in nozzle needle (5) the control of turning chamber (4) was 50% of fuel-supplying pressure at least.
7. according to the common-rail injector (1) of claim 3, it is characterized in that: described sliding pin element (3) and described valve element (2) are separated to form.
8. according to the common-rail injector (1) of claim 3, it is characterized in that: the two ends of described sliding pin element (3) are shaped as the pin shape of diameter less than the slip diameter.
9. according to the common-rail injector (1) of claim 3, it is characterized in that: described sliding pin element (3) is formed into a cylindrical pin with constant diameter, and the end of leading to the described sliding eye of described low voltage side valve seat (22) has an expansion (31a) that diameter is bigger, the end (3a) of described sliding pin element (3) is arranged in described expansion (31a), and described throttle valve part (32) forms to this expansion (31a) opening.
10. according to the common-rail injector (1) of claim 3, it is characterized in that: its slip surface at least of described sliding pin element (3) is made by superhard material or stupalith.
11. the common-rail injector (1) according to claim 3 is characterized in that: described sliding pin element (3) is made by the superhard material that Young's modulus is higher than metal.
12. the common-rail injector (1) according to claim 3 is characterized in that: the upstream side at described high pressure side valve seat (23) is provided with a valve spring (24), is used for to low voltage side valve seat (22) the described valve element of bias voltage (2).
13. the common-rail injector (1) according to claim 3 is characterized in that:
Wherein Ds is the diameter of the nozzle valve seat at nozzle needle place, Dc is the slip diameter in control room, Fk is that nozzle is provided with load, Pc is from the fuel-supplying pressure of rail altogether, and kpo can make pressure in nozzle needle (5) the control of turning chamber (4) with respect to the ratio of fuel-supplying pressure when Pc is maximum supply pressure.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP198866/2004 | 2004-07-06 | ||
| JP2004198866 | 2004-07-06 | ||
| JP158576/2005 | 2005-05-31 |
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| Publication Number | Publication Date |
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| CN1719021A CN1719021A (en) | 2006-01-11 |
| CN100432415C true CN100432415C (en) | 2008-11-12 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2005100818938A Active CN100432415C (en) | 2004-07-06 | 2005-07-06 | Common-rail injector |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP4952737B2 (en) |
| CN (1) | CN100432415C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102656360A (en) * | 2009-12-08 | 2012-09-05 | 罗伯特·博世有限公司 | Fuel injection device having needle position determination |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012202251A (en) * | 2011-03-24 | 2012-10-22 | Denso Corp | Injector |
| GB201411162D0 (en) * | 2014-06-24 | 2014-08-06 | Delphi International Operations Luxembourg S.�.R.L. | Control valve |
| JP6443109B2 (en) * | 2015-02-17 | 2018-12-26 | 株式会社Ｓｏｋｅｎ | Fuel injection valve |
| CN108869131B (en) * | 2018-07-25 | 2023-08-29 | 中国人民解放军海军工程大学 | Supercharger and ultrahigh-pressure common rail system comprising same |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2500828Y (en) * | 2001-10-19 | 2002-07-17 | 清华大学 | Electrocontrolled oil injector for electrocontrolled high-pressure common rail diesel oil injecting system |
| WO2003004861A1 (en) * | 2001-07-04 | 2003-01-16 | Robert Bosch Gmbh | Fuel injector comprising a force-balanced control valve |
| US6719264B2 (en) * | 2000-04-20 | 2004-04-13 | Robert Bosch Gmbh | Valve for controlling fluids |
| WO2004051071A1 (en) * | 2002-12-05 | 2004-06-17 | Robert Bosch Gmbh | Fuel injection device comprising a 3/3-way control valve for forming the injection process |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001140726A (en) * | 1998-12-09 | 2001-05-22 | Denso Corp | Valve device and fuel injector using it |
| JP4025476B2 (en) * | 1999-11-12 | 2007-12-19 | 株式会社日本自動車部品総合研究所 | Injector |
| JP2003148283A (en) * | 2001-11-06 | 2003-05-21 | Denso Corp | Valve unit and fuel injection device using the same |
| JP4161635B2 (en) * | 2002-08-19 | 2008-10-08 | 株式会社デンソー | Fuel injection control device |
| DE10254749A1 (en) * | 2002-11-23 | 2004-06-17 | Robert Bosch Gmbh | Fuel injection device with a 3/3-way control valve for injection course shaping |
-
2005
- 2005-07-06 CN CNB2005100818938A patent/CN100432415C/en active Active
-
2009
- 2009-03-19 JP JP2009068543A patent/JP4952737B2/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6719264B2 (en) * | 2000-04-20 | 2004-04-13 | Robert Bosch Gmbh | Valve for controlling fluids |
| WO2003004861A1 (en) * | 2001-07-04 | 2003-01-16 | Robert Bosch Gmbh | Fuel injector comprising a force-balanced control valve |
| CN2500828Y (en) * | 2001-10-19 | 2002-07-17 | 清华大学 | Electrocontrolled oil injector for electrocontrolled high-pressure common rail diesel oil injecting system |
| WO2004051071A1 (en) * | 2002-12-05 | 2004-06-17 | Robert Bosch Gmbh | Fuel injection device comprising a 3/3-way control valve for forming the injection process |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102656360A (en) * | 2009-12-08 | 2012-09-05 | 罗伯特·博世有限公司 | Fuel injection device having needle position determination |
| CN102656360B (en) * | 2009-12-08 | 2016-03-23 | 罗伯特·博世有限公司 | There is the fuel injection system of the position determination mechanism of valve needle |
| US9856842B2 (en) | 2009-12-08 | 2018-01-02 | Robert Bosch Gmbh | Fuel injection device having a needle position determination |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1719021A (en) | 2006-01-11 |
| JP2009133324A (en) | 2009-06-18 |
| JP4952737B2 (en) | 2012-06-13 |
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