DE102004024282A1 - Pump-nozzle unit for internal combustion engine has control valve operated by hydraulic intensifier with first intensifying piston provided with blind hole in which is guided and sealed second intensifying piston - Google Patents

Abstract

The pump-nozzle unit, or pump-pipe-nozzle unit, for an internal combustion engine has a pump element with a pump chamber, and a control valve (5) with a valve component (25) operated by a hydraulic intensifier (21) with a first (35) and a second (33) intensifying piston. The first intensifying piston has a blind hole (37), and the second intensifying piston is guided and sealed in the blind hole, or the second intensifying piston has a blind hole, with the first intensifying piston guided and sealed in it.

Description

The The invention relates to a pump-nozzle unit (PDE) and a Pump-Line-Nozzle-Unit (PLD) for one Internal combustion engine, with a pump element, wherein the pump element a pump chamber, and with a control valve, the one hydraulic connection between the pump room and a low-pressure fuel supply opens or closes wherein a valve member of the control valve by a hydraulic translator with a first booster piston and a second booster piston actuated becomes.

in the In the context of the invention, the following will be referred to only as the unit injector (PDE). spoken, although always a pump-line-nozzle unit (PLDE) is meant. The essential difference between a PDE fuel injection system and a PLDE fuel injection system is that in a PDE the pump element and the associated injector in the immediate spatial Close to each other are arranged while in a PLDE between the pump element and the injector a spatial Distance may be present, which is bridged by a high pressure line.

A PDE is for example from the DE 198 37 333 A1 known. However, in this PDE no hydraulic translator is provided because the valve member of the control valve is actuated by an electromagnet.

Hydraulic translators for operation the valve member are always required if the intended Actuator, although a high force, but only a small travel has, as is the case for example with piezo actuators. The usage of piezo actuators in connection with PDE or PLDE systems failed so far, that the space requirement for the hydraulic translator and the piezo actuator was too big.

Of the Invention is based on the object, a PDE and a PLDE for an internal combustion engine provide compact, yet extremely short switching times enable.

These Task is according to the invention in a Pump-nozzle unit or pump-line-nozzle unit for one Internal combustion engine, with a pump element, wherein the pump element a pump chamber, and with a control valve, the one hydraulic connection between the pump room and a low-pressure fuel supply opens or closes wherein a valve member of the control valve by a hydraulic translator with a first booster piston and a second booster piston actuated is solved by that the first translator piston has a blind hole, and that the second booster piston in the blind hole bore sealed is.

In a quasi-kinematic reversal of this embodiment of the invention The object of the invention is based on a pump-nozzle unit or pump-line-nozzle unit for an internal combustion engine with a pumping element, wherein the pumping element comprises a pumping space has, and with a control valve, a hydraulic connection between the pump room and a low-pressure fuel supply opens or closes wherein a valve member of the control valve by a hydraulic translator with a first booster piston and a second booster piston actuated is also solved by that the second booster piston has a blind hole, and that the first booster piston in the blind hole bore sealed is.

Advantages of invention

Both solutions according to the invention are common, that the space requirement of the hydraulic booster according to the invention is greatly reduced by that first booster piston and second booster piston at least partially enclose each other. Because of the small footprint for the hydraulic translator Is it possible, a PDE as well as a PLDE with hydraulic translator and piezo actuator too realize. Through the piezo actuator can the required big ones restoring forces be realized readily enough with sufficiently short switching times. This makes it possible Inject even the smallest injection quantities with the required precision and thus the operating behavior and the emission behavior of the internal combustion engine in different load conditions to improve.

at A variant of the invention provides that the second booster piston and the valve member in one piece accomplished or the second translator piston and the valve member are firmly connected. The solid connection between second translator piston and valve member can be made for example by a thread. As a result, the space requirement for the combination of hydraulic translator and control valve again reduced, which naturally has a positive effect on the whole Space requirement of the unit injector unit or the pump-line-nozzle unit effect.

It is particularly advantageous if the first booster piston is actuated by a piezoactuator is because with the help of the piezo actuator large actuating forces and very short switching times can be realized.

In further supplement The invention provides that an end face of the first booster piston and an end face of the second booster piston a translator room limit, and that the frontal area of the first booster piston is greater than the face of the second booster piston is. This ensures that that a small travel of the first booster piston, the example actuated by a piezo actuator becomes, in a larger travel the second booster piston, as he is for example the control valve is required is converted.

at some embodiments of the invention of the hydraulic translator It has proved to be advantageous if the compiler space formed in two parts is, and that the two parts of the interpreter room through a connecting hole hydraulically connected to each other.

In further supplement The invention provides that the compiler space in the radial direction from a sleeve is limited. This makes it possible that despite the tight fit between the blind bore and the booster piston the first translator piston and the second translator piston can move easily relative to each other, as the sleeve itself automatically to the translator pistons centered and thus compensated for misalignment in the production can be without it being the hydraulic translator according to the invention sluggishly becomes.

Around a good seal of the translator's room is further provided that the sleeve of at least a first Compression spring against a housing is pressed, and that the first compression spring either one end against the first booster piston or at one end against the second booster piston is supported.

to further improvement of the sealing of the translation room is that the sleeve is a biting edge having.

The Function of the unit injector or the pump-line-nozzle unit according to the invention will be further improved if a second compression spring is provided, the valve member of the control valve in the direction of an open position of the control valve acted upon by a spring force.

alternative can in other embodiments the invention may also be provided a third compression spring, which is the Valve member of the control valve in the direction of a closed position of the control valve acted upon by a spring force. Which of the two variants of the invention in individual cases the preference is given depends on the other conditions from.

Around in any operating condition, even when the actuator is switched off unique position of the first booster piston relative to the second booster piston To have a fourth compression spring can be provided, which is at one end against the first booster piston and the other end is supported against the second booster piston.

The Function of the pump-nozzle unit according to the invention and the pump-line-nozzle unit according to the invention is further improved when in the second booster piston and in the valve member at least a leakage discharge bore is provided. This ensures reliable, that neither the first booster piston still the second translator piston can be blocked by leakage.

Further Advantages and advantageous embodiments of the invention are the subsequent drawing, the description and the claims can be removed.

All in the drawing, the description and the claims described Features can both individually and in any combination with each other invention essential be.

drawings

It demonstrate:

1 a first embodiment of a PDE system according to the invention with a control valve shown schematically;

2 a first embodiment of a control valve according to the invention with hydraulic booster and piezo actuator;

3 A second embodiment of a control valve according to the invention with hydraulic translator and piezo actuator;

4 a third embodiment of a control valve according to the invention with hydraulic booster and piezo actuator; and

5 A fourth embodiment of a control valve according to the invention with hydraulic booster and piezo actuator.

description the embodiments

In 1 is a unit injector unit in its entirety by the reference numeral 1 characterized. The PDE 1 is used for fuel injection into a combustion chamber of a direct injection internal combustion engine (not shown). It has a pump element 2 on, which builds up the required injection pressure. Via an injection nozzle 3 becomes that of the pump element 2 Fuel injected under high pressure is injected into the combustion chamber (not shown).

The pump-nozzle unit is controlled 1 from a 2/2-way control valve shown as a block diagram 5 ,

The control valve 5 is from an in 1 Actuator, not shown, in particular a piezo actuator, driven.

As with any PDE form the pump element 2 and the injector 3 one unity. For each cylinder of the internal combustion engine is a PDE 1 in the cylinder head 7 the internal combustion engine installed and either directly via a plunger or indirectly via rocker arm of a camshaft of the internal combustion engine (not shown) via an actuating element 8th driven.

A pump room 9 of the pump element 2 is about a fuel feed 11 with a low-pressure fuel supply, not shown 12 connected. The low pressure fuel supply 12 can, for example, an electrically driven feed pump 15 and a fuel filter (not shown), which via a line fuel from a fuel tank 13 suck in

The control valve 5 divides the fuel feed into two sections 11a and 11b , The control valve 5 is controlled by a control unit, not shown, and opens, as in 1 shown, the hydraulic connection between the pump room 9 and the tank 13 or closes these (not shown). The section of the fuel inlet 11 which is located between the control valve 5 and the pre-feed pump 15 have in 1 the reference number 11a designated during the section between the control valve 5 and the pump room 9 with the reference number 11b was provided.

When the control valve 5 is open during the suction stroke of the pump piston 10 Fuel in the pump room 9 flow. In the subsequent delivery stroke of the pump piston 10 is the previously in the pump room 9 pumped fuel back into the tank 13 promoted as long as the control valve 5 is open. This also means that in the pump room 9 insufficient pressure builds up around the injector 3 to open.

When fuel through the injector 3 is to be injected into the combustion chamber, not shown, of the internal combustion engine, the control valve 5 during the delivery stroke of the pump piston 10 closed. This allows the fuel from the pump room 9 not in the tank anymore 13 be pumped back and it builds in the pump room 9 a high pressure on, which eventually opens the injector 3 and thus leads to the injection of fuel into the combustion chamber (not shown) of the internal combustion engine. By the closing time of the control valve 5 the beginning of the injection of fuel into the combustion chamber can be determined. The injection of fuel into the combustion chamber is terminated by the control valve 5 is opened again.

Based on 2 - 5 Below are various embodiments of inventive control valves 5 described and explained in detail. The same components have the same reference numerals and it is to avoid repetition, referred to the above.

In the cylinder head 7 and a housing 17 the pump-nozzle unit 1 are leakage lines 19 provided, which serve, possibly occurring leaks on the pump element 2 , the injector 3 or the control valve 5 dissipate. In the first embodiment according to 2 are the control valve 5 and a hydraulic translator 21 constructed so that overall results in a very small footprint.

The control valve 5 is as a seat valve with a in the housing 17 elaborated valve seat 23 educated. With this valve seat 23 acts a valve member 25 together. If, as in 1 shown, the valve member 25 on the valve seat 23 rests, the connection between the sections becomes 11a and llb of the fuel feed 11 interrupted. This means that, firstly, no fuel left the tank 13 in the pump room 9 (please refer 1 ) and secondly in the pump room 9 builds up a pressure when the pump piston 10 moves from its bottom dead center toward top dead center (delivery stroke).

As soon as the valve member 25 from the valve seat 23 lifts off (not shown), breaks the pressure in the pump room 9 together and the hydraulic connection between the tank 13 and the pump room 9 is restored. The valve member 25 is constructed like a conventional cone seat valve. In the lower part of 2 is the valve member 25 in a stepped bore 27 guided. This is followed by a recess 29 and a frusto-conical section 31 of the valve member 25 at. At the upper end of the frusto-conical section 31 goes the valve member 25 into a second booster piston 33 above. This means that valve member 25 and second translator piston 33 are made in one piece in this embodiment. This results in a first significant savings in space at the control valve 5 and the hydraulic translator 21 ,

The hydraulic translator 21 consists essentially of a first booster piston 35 with a blind hole 37 in which the second booster piston 33 is guided sealingly.

At the outer diameter D1 of the first booster piston 35 is a sleeve 39 present through the first booster piston 35 is guided free of play and sealing in the radial direction. Between the first booster piston 35 and the sleeve 39 is a first compression spring 41 clamped, leaving the sleeve 39 against the case 17 of the control valve 5 or the hydraulic translator 21 is pressed. To the seal between the sleeve 39 and the housing 17 to improve, rejects the sleeve 39 a biting edge 43 on. To the contact pressure of the sleeve 39 on the case 17 can continue to increase, as in 2 shown, an additional Bourdon tube 45 between sleeve 39 and first booster piston 35 be provided.

At the top of the first booster piston 35 is a piezo actuator 47 provided, which the first booster piston 35 in the direction of an arrow 49 moves when a voltage is applied to the piezo actuator 47 is created. An annular end face 51 with an outer diameter D ₁ and an inner diameter D _{2 of} the first booster piston 35 as well as an end face 53 of the second booster piston 33 define a two-part translator space in the axial direction 55a and 55b , Through a connection hole 57 become the two parts of the Translator Room 25 hydraulically connected.

The face 53 of the second booster piston 33 has the diameter D ₂ .

As the force of a piezo actuator 47 very large and whose travel is relatively small, the hydraulic translator needs 21 be designed so that the end face 51 of the first booster piston is greater than the end face 53 of the second booster piston.

If the piezo actuator 47 de-energized, it contracts in the axial direction, so that the first booster piston 35 in 2 moved upwards (not shown). As a result, the volume of the part decreases 55b the translator's room 55 to. To the same extent decreases the volume of the part 55a the translator's room 55 off, leaving the second booster piston 33 in 2 moved upwards. As a result, that notes with the second booster piston 33 connected valve member 25 from the valve seat 23 off and provides the hydraulic connection between the parts 11a and IIb the fuel supply ago.

To lift off the valve member 25 from the valve seat 23 with de-energized piezo actuator 47 Ensure is at the bottom of the valve member 25 a second compression spring 59 provided, which at one end against the housing 17 and at the other end against the valve member 25 supported.

Characterized in that in the inventive hydraulic booster, the second booster piston 33 in the blind hole 37 of the first booster piston 35 is taken up, the space required for the hydraulic translator is reduced 21 considerably. The result is the piezo actuator 47 , the hydraulic translator 21 and the control valve 25 designed very compact, so that despite limited space on an internal combustion engine, the realization of a PDE or a PLDE with a piezoelectric actuator 47 and the resulting advantages known per se can be realized.

In the valve member 25 is a leakage drainage hole 61 provided, any leaks between the valve member 25 and the stepped bore 27 in the section 11a dissipates the fuel supply. How out 2 As can be seen, there is the leakage discharge hole 61 from two mutually perpendicular partial bores.

In 3 is a second embodiment of a hydraulic translator according to the invention 21 and a control valve according to the invention 5 shown. The same components are provided with the same reference numerals and it is to avoid repetition, only the differences from the embodiment according to 2 explained. In the second embodiment, the translator room 55 formed in one piece. This means that the end face 53 of the second booster piston 33 is also an annular surface whose outer diameter D ₂ and the inner diameter in 3 denoted by D ₃ . Again, the end face 51 of the first booster piston 35 bigger than the face 53 of the second booster piston 33 have to be.

In this embodiment, in addition to the second compression spring 59 a third compression spring 63 between the first booster piston 35 and second translator piston 33 provided, that of the second compression spring 59 counteracts. Spring rate and preload of second compression spring 59 and third compression spring 63 are so coordinated that with de-energized piezo actuator 47 the valve member 25 from the valve seat 23 takes off and thus the control valve 5 is open.

Because of the mountability in this embodiment, the second booster piston 33 and the valve member 25 not be made in one piece. Therefore, the lower part of the valve member 25 by means of a thread 65 with the upper part of the valve member 25 and the second booster piston 33 screwed. So that the screw connection between the lower part of the valve member 25 with the tapered section 31 and the upper part of the valve member 25 can not solve, is also a fuse element 67 , such as a Seeger ring. Also in this embodiment results in a very compact design of the hydraulic booster 21 and the control valve 5 ,

At the in 4 illustrated third embodiment, the valve member 25 and the second translator piston 33 again in one piece. Also the translator room 55 is in two parts with the subspaces 55a and 55b , The essential difference from the first embodiment is that in the third embodiment, the second booster piston 33 a blind hole 59 in which the first booster piston 35 is guided sealingly. The connection hole 57 which the subspaces 55a and 55b of the compiler room is in this embodiment in the first booster piston 35 intended. Also in this embodiment, the control valve is normally open, since the valve member 25 through the second compression spring 59 from the valve seat 23 is lifted as soon as the piezoelectric reactor, not shown 47 is switched off. In this embodiment, care must be taken that the spring rates of the first compression spring 41 and the second compression spring 59 are coordinated with each other so that with unpressurized translator room 55 the valve member 25 from the valve seat 23 takes off.

Also in the third embodiment, the end face 53 of the first booster piston 35 with the outer diameter D _{1 be} greater than the end face 53 of the second booster piston 33 , which is annular and is limited by the diameter D ₂ and D ₁ .

In 5 a fourth embodiment is shown, in which the control valve 5 is closed normally. The required closing force is provided by the second compression spring 59 applied. Also in this embodiment, because of the mountability of hydraulic translator 21 and control valve 5 the second booster piston 33 and the valve member 25 be carried out in two parts. The structural design of the connection between the second booster piston 33 and valve member 25 is in 5 not shown in detail. However, it is possible, for example, by a thread or similar, known from the prior art connection techniques to connect these two components together in a suitable manner.

In this embodiment, in the second booster piston 33 a blind hole 69 present in which the first booster piston 35 is guided sealingly with its outer diameter D1.

The translator room 55 is made in one piece in this embodiment. The annular end face of the first booster piston 35 with the outer diameter D ₁ and an inner diameter D ₂ must be greater than the annular end face 53 of the second booster piston 33 , which is limited by the diameter D ₃ and D ₁ .

If the piezo actuator, not shown 47 the first booster piston 35 in the direction of the arrow 49 As a result, the second booster piston moves 33 in 5 moved down, leaving the frusto-conical section 31 of the valve member 25 from the valve seat 23 lifts and thus the hydraulic connection between the section 11a and llb the fuel supply 11 will be produced.

Also in this embodiment, a very compact design can be achieved both the hydraulic booster and the control valve 5 ,

Claims (14)

Pump-nozzle unit or pump-line-nozzle unit for an internal combustion engine, with a pump element ( 2 ), wherein the pump element ( 2 ) a pump room ( 9 ), and with a control valve ( 5 ), which is a hydraulic connection ( 11 ) between the pump room ( 9 ) and a low pressure fuel supply ( 12 ) opens or closes, with a valve member ( 25 ) of the control valve ( 5 ) by a hydraulic translator ( 21 ) with a first booster piston ( 35 ) and a second booster piston ( 33 ), characterized in that the first booster piston ( 35 ) a blind hole ( 37 ), and that the second booster piston ( 33 ) in the blind hole ( 37 ) is guided sealing. ( 2 ) Pump-nozzle unit or pump-line-nozzle unit for an internal combustion engine, with a pump element ( 2 ), wherein the pump element ( 2 ) a pump room ( 9 ), and with a control valve ( 5 ), which is a hydraulic connection ( 11 ) between the pump room ( 9 ) and a low pressure fuel supply ( 12 ) opens or closes, wherein a valve member ( 25 ) of the control valve ( 5 ) by a hydraulic translator ( 21 ) with a first booster piston ( 35 ) and a second booster piston ( 33 ), characterized in that the second booster piston ( 33 ) a blind hole ( 69 ), and that the first booster piston ( 35 ) in the blind hole ( 69 ) is guided sealing. ( 4 and 5 ) Pump-nozzle unit or pump-line-nozzle unit according to one of the preceding claims, characterized in that the second booster piston ( 33 ) and the valve member ( 25 ) are made in one piece. Pump-nozzle unit or pump-line-nozzle unit according to one of the preceding claims, characterized in that the second booster piston ( 33 ) and the valve member ( 25 ) are firmly connected. Pump-nozzle unit or pump-line-nozzle unit according to one of the preceding claims, characterized in that the first booster piston ( 35 ) of an actuator, in particular a piezo actuator ( 47 ), is operated. Pump-nozzle unit or pump-line-nozzle unit according to one of the preceding claims, characterized in that an end face ( 51 ) of the first booster piston ( 35 ) and an end face ( 53 ) of the second booster piston ( 33 ) a translator room ( 55 ), and that the end face ( 51 ) of the first booster piston ( 35 ) larger than the end face ( 53 ) of the second booster piston ( 33 ). Pump-nozzle unit or pump-line-nozzle unit according to claim 6, characterized in that the compiler space ( 55 ) is formed in two parts, and that the two parts ( 55a . 55b ) of the translator room ( 55 ) through a connecting bore ( 57 ) are hydraulically connected. Pump-nozzle unit or pump-line-nozzle unit according to one of claims 6 or 7, characterized in that the compiler space ( 55 ) in the radial direction of a sleeve ( 39 ) is limited. Pump-nozzle unit or pump-line-nozzle unit according to claim 8, characterized in that the sleeve ( 39 ) at least from a first compression spring ( 41 ) against a housing ( 17 ) of the hydraulic translator ( 21 ) is pressed, and that the first compression spring ( 41 ) one end either against the first booster piston ( 33 , please refer 2 and 3 ), against the second booster piston ( 35 , please refer 4 ) or against the housing ( 17 . 5 ) is supported. Pump-nozzle unit or pump-line-nozzle unit according to claim 8 or 9, characterized in that the sleeve ( 39 ) a biting edge ( 43 ) having. Pump-nozzle unit or pump-line-nozzle unit according to one of the preceding claims, characterized in that a second compression spring ( 59 ) is provided, and that the second compression spring ( 59 ) the valve member ( 25 ) of the control valve (14) in the direction of an opening position of the control valve (FIG. 5 ) acted upon by a spring force ( 2 and 4 ). Pump-nozzle unit or pump-line-nozzle unit according to one of the preceding claims, characterized in that a second compression spring ( 59 ) is provided, and that the second compression spring ( 59 ) the valve member ( 25 ) of the control valve ( 5 ) in the direction of a closed position of the control valve ( 5 ) acted upon by a spring force ( 3 and 5 ). Pump-nozzle unit or pump-line-nozzle unit according to one of the preceding claims, characterized in that a third compression spring ( 63 ) is provided, and that the third compression spring ( 63 ) at one end against the first booster piston ( 35 ) and at the other end against the second booster piston ( 33 ) ( 3 ). Pump-nozzle unit or pump-line-nozzle unit according to one of the preceding claims, characterized in that in the second booster piston ( 33 ) and in the valve member ( 25 ) at least one leakage discharge bore ( 61 ) is provided.