WO2008122521A1

WO2008122521A1 - Valve and injection system for an internal combustion engine comprising a valve

Info

Publication number: WO2008122521A1
Application number: PCT/EP2008/053645
Authority: WO
Inventors: Fredrik Borchsenius; Anatoliy Lyubar
Original assignee: Continental Automotive Gmbh
Priority date: 2007-04-05
Filing date: 2008-03-27
Publication date: 2008-10-16
Also published as: DE102007016625A1

Abstract

The invention relates to a valve (22) comprising a valve housing (50) with a valve housing cavity (52), a wall (66), a fluid inlet (54) and a fluid outlet (56) that are situated in said valve housing (50) and can be hydraulically coupled to the valve housing cavity (52), a sealing seat (62, 64) that is formed in the wall (66) of the valve housing cavity (52), a valve body (58) that can be axially displaced in the valve housing cavity (52) between the fluid inlet (54) and the fluid outlet (56), said body having a seat region (68, 70) that co-operates with the sealing seat (62, 64) in such a way that in a closed position a throughput of fluid through the fluid outlet (56) is prevented and otherwise a fluid throughput through the fluid outlet (56) is released, and a spring element (60) that applies a force to the valve body (58). In a first fluid pressure range at the fluid inlet (54) below a first fluid pressure value (P_l), a fluid throughput through the fluid outlet (56) is prevented. In a second fluid pressure range above a second fluid pressure value (P_2), a fluid output through the fluid outlet (56) is permitted at a maximum first fluid throughput value (FR_1). In a third fluid pressure range above the first fluid pressure value (P_l) and below the second fluid pressure value (P_2), a fluid output through the fluid outlet (56) is permitted at a maximum second fluid throughput value (FR_2) that is greater than the first fluid throughput value (FR_1).

Description

description

Valve and injection system for an internal combustion engine with valve

The invention relates to a valve and an injection system for an internal combustion engine with valve.

For injecting fuel into the combustion chambers of an internal combustion engine, in particular a diesel internal combustion engine, injection systems are used which have increasingly been designed as so-called "common rail" systems in recent years The fuel to be injected is present in the fuel reservoir at a pressure of up to 2000 bar.

Injection systems for internal combustion engines usually have various pumps and valves, by means of which combustion chambers of the internal combustion engine fuel can be metered. Such injection systems for internal combustion engines place high demands on the accuracy of the injection pressure required for injecting the fuel into the combustion chambers of the internal combustion engine.

This is particularly important as ever stricter legislation is enacted regarding permissible pollutant emissions from internal combustion engines located in motor vehicles. These make it necessary to carry out various measures by which the pollutant emissions are reduced. For example, the formation of soot is highly dependent on the preparation of the air / fuel mixture in the respective cylinder of the internal combustion engine. The injection system can achieve a high accuracy of the injection pressure of the fuel into the combustion chamber of the internal combustion engine with suitable control and regulating units such as corresponding valves.

The invention has for its object to provide a valve that is simple. Furthermore, the invention has for its object to provide an injection system with a valve which allows a high accuracy of the injection pressure of the fuel in the combustion chambers of the internal combustion engine and a simple structure of the injection system.

The task is solved by the characteristics of the independent ones

Claims. Advantageous embodiments of the invention are characterized in the subclaims.

According to a first aspect, the invention is characterized by a valve having a valve housing with a longitudinal axis, which has a Ventilgehauseausnehmung with a wall, a Fluideintrittsoffnung and a Fluidaustrittsoffnung which are arranged in the valve housing and hydraulically coupled to the Ventilgehauseausnehmung, one at the Wall of Ventilgehauseausnehmung trained sealing seat, a in the Ventilgehauseausnehmung between the Fluideintrittsoff- and the Fluidaustrittsoffnung axially movable valve body having a seating which cooperates with the sealing seat so that in a closed position prevents fluid flow through the Fluidaustrittsoffnung and otherwise the fluid flow rate the fluid outlet opening is released, and a spring element, by means of which the valve body can be acted upon with force in the direction of the fluid inlet opening, wherein the valve body and the spring element are designed and arranged in this way et are that in a first Preventing the range of fluid pressure at the Fluideintrittsoffnung below a first fluid pressure value of the fluid flow through the Fluidaustrittsoffnung that in a second region of the fluid pressure at the Fluideintrittsoffnung o- above a second fluid pressure value is a fluid through the Fluidaustrittsoffnung with a maximum first fluid flow rate allows, and that in a fluid flow rate through the Fluidaustrittsoff- tion with a maximum second fluid flow rate is greater than the first fluid flow rate allows a third range of fluid pressure at the Fluideintrittsoffnung above the first fluid pressure value and below the second fluid pressure.

This has the advantage that at medium fluid pressures between the first fluid pressure value and the second fluid pressure value, a large fluid flow through the valve is possible, while at low and high fluid pressures, a small fluid flow or an inhibition of the fluid flow is possible.

In an advantageous embodiment of the invention, the valve body and the sealing seat are designed and arranged such that in a fourth region of the fluid pressure at the Fluideintrittsoffnung above the first fluid pressure value and below a third fluid pressure value, a variation of FIu- iddurchsatzes by the Fluidaustrittsoffnung between zero and the maximum second fluid flow rate is allowed, and in a fifth range of the fluid pressure at the fluid inlet above the third fluid pressure value and below the second fluid pressure value, a variation of fluid throughput through the fluid outlet between the maximum second fluid flow rate and the maximum first fluid flow rate is enabled, the fourth range the fluid pressure at the fluid inlet opening is smaller than the fifth area of the fluid pressure at the fluid inlet opening. This has the advantage that an increase in the fluid throughput Set of zero to the second fluid pressure value in a small fluid pressure range and a drop in the fluid flow rate of the second fluid pressure value to the first fluid pressure value in a large fluid pressure range are possible.

In a further advantageous embodiment of the invention, the valve has a first sealing seat formed on the wall of the Ventilgehauseausnehmung and formed on the wall of Ventilgehauseausnehmung second sealing seat which is axially spaced from the first sealing seat, wherein the valve body axially between the first sealing seat and the second sealing seat is arranged, and the Ventilkorper having a first seating, which cooperates with the first sealing seat so that in the first region of the fluid pressure at the Fluideintrittsoffnung below the first fluid pressure value, a fluid flow rate is prevented by the Fluidaustrittsoffnung, and the Ventilkorper a second seating area which cooperates with the second sealing seat so that in the second region of the fluid pressure at the fluid inlet opening above the second fluid pressure value, a fluid flow is prevented by the Fluidaustrittsoffnung. This has the advantage that a simple construction of the valve with two sealing seats and a valve body for realizing a fluid throughput in the middle pressure range between the first fluid pressure value and the second fluid pressure value is possible.

In a further advantageous embodiment of the invention, the first sealing seat is konusformig formed with a first Kegeloffnungswinkel and the second sealing seat kon nusformig formed with a second Kegeloffnungswinkel, and the first cone opening angle of the first sealing seat is greater than the second Kegeloffnungswinkel of the second sealing seat. This allows a simple realization of an increase in the fluid flow rate from zero to the second fluid pressure value in a small fluid pressure range and a decrease in the fluid pressure. if the fluid flow rate from the second fluid pressure value to the first fluid pressure value in a large fluid pressure range.

In a further advantageous embodiment of the invention, the first seat portion of the Ventilkorpers is konusformig formed with a first Kegeloffnungswinkel and the second seating area of Ventilkorpers is konusformig formed with a second Kegeloffnungswinkel, and the first Kegeloff- angle of the first seat portion is smaller than the second Kegeloffnungswinkel of the second seating area. This has the advantage that a simple realization of an increase of the fluid flow rate from zero to the second fluid pressure value in a small fluid pressure range and a decrease of the fluid flow rate from the second fluid pressure value to the first fluid pressure value in a large fluid pressure range is possible.

In a further advantageous embodiment of the invention, the Ventilkorper on a cylinder portion, and the wall of the Ventilgehauseausnehmung has a cylindrical portion, and the Ventilkorper is arranged in the Ventilgehauseausnehmung that between the cylinder portion of the Ventilkorpers and the cylinder portion of the wall of the Ventilgehauseausnehmung Gap is formed with a gap length, such that in the third region of the fluid pressure at the Fluideintrittsoffnung above the first Fluiddruck- value and below the second fluid pressure value, the gap length in dependence on the fluid pressure at the Fluideintritt- soffnung is variable, wherein for the first fluid pressure value a minimum gap length value and for the second fluid pressure value a maximum gap length value is assumed. This has the advantage that the fluid throughput through the valve in the third region of the fluid pressure at the fluid inlet opening can be controlled as a function of the gap length. According to a second aspect, the invention comprises an injection system for an internal combustion engine, with at least one injector coupled to a fuel reservoir, a demand pump for requesting fuel from a fuel tank, a high-pressure pump downstream of the charge pump, for requesting the fuel into the fuel storage, a downstream of the high-pressure pump valve according to the first aspect of the invention, with which the pressure to be established in the fuel reservoir is adjustable.

This has the advantage that the pressure to be produced in the fuel reservoir of the injection system can be adjusted in a simple manner by means of the valve, in particular in the fluid pressure range between the first fluid pressure value and the second fluid pressure value. Below the first fluid pressure value, the flow of fluid through the valve can be prevented in order to enable safe startup of the injection system. Above the second fluid pressure value, the fluid throughput through the valve can also be prevented or kept very small in order to avoid unnecessary fluid loss and thus unnecessary energy loss of the injection system. Furthermore, can be saved with the valve an expensive pressure control valve, which can be dispensed with a control circuit for adjusting the pressure in the fuel tank of the injection system.

In an advantageous embodiment of the second aspect of the invention, a volume flow control valve is arranged hydraulically between the pre-demand pump and the high-pressure pump, with which the fuel flow from the pre-demand pump is adjustable in the high-pressure pump. This has the advantage that the volume flow control valve can work over the entire control range as an actuator to be set active, thereby the control can be simple and precise durchfuhrbar.

Exemplary embodiments of the invention are explained in more detail below with reference to schematic drawings.

Show it:

1 shows a block diagram of an injection system for an internal combustion engine with a valve,

FIG. 2 shows a schematic cross section through a valve in a first embodiment,

3a shows the course of the effective throttle area of the first embodiment of the valve in dependence on the inlet pressure,

FIG. 3b shows the profile of the fluid flow rate of the first embodiment of the valve as a function of the inlet pressure,

FIG. 4 shows a schematic cross section through a valve in a second embodiment,

Figure 5a shows the course of the gap length of the second embodiment of the valve as a function of the inlet pressure, and

FIG. 5b shows the course of the fluid flow rate of the second embodiment of the valve as a function of the inlet pressure.

FIG. 1 shows an injection system for an internal combustion engine, with a fuel tank 10, from which fuel is required by means of a pre-demand pump 12. The Vorforderpumpe 12 can be mechanically driven by a (not shown) drive shaft, the arrival Drive shaft may be fixedly coupled to a motor shaft of the internal combustion engine. Alternatively, it is also possible to operate the front-end pump 12 electrically, whereby a control of the Forderleistung the Vorforderpumpe 12 is independent of the Forderleistung other pumps possible.

The Vorforderpumpe 12 is hydraulically coupled on the output side with a form control valve 28, which returns a part of the demanded by the Vorforderpumpe 12 fuel to the suction side of the Vorforderpumpe 12 when exceeding a predetermined fuel pressure at the output side of the Vorforderpumpe 12 and thus the fuel pressure at the output side of the Vorforderpumpe 12 largely constant.

Downstream of the pre-demand pump 12, a high-pressure pump 14, which requests fuel into a fuel reservoir 16 via a fuel storage supply line 44. By the high-pressure pump 14, the fuel to be injected by means of injectors 18 in combustion chambers of the internal combustion engine, reach a relatively high injection pressure. The high pressure pump 14 may preferably be formed as a radial piston pump or as a series piston pump with a plurality of cylinder units, as are known for use in injection systems of internal combustion engines.

The high-pressure pump 14 is connected downstream to the fuel accumulator 16, which in turn is hydraulically coupled via lines to the one injector 18 or a plurality of injectors 18. Each of the injectors 18 is associated with a combustion chamber of the internal combustion engine and each can be controlled so that fuel is injected into the combustion chamber. Excess fuel can be returned from the injectors 18 via an Inj ektorrucklaufleitung 46 to the fuel tank 10. In a downstream of the high-pressure pump 14 and upstream of the fuel reservoir 16 branching line 42, a valve 22 is arranged. When a predetermined fuel pressure is exceeded, the valve 22 opens, and a partial flow of the fuel demanded by the high-pressure pump 14 can be returned to the fuel tank 10 via the line 42 branching off downstream of the high-pressure pump 14 and upstream of the fuel reservoir 16.

Between the Vorforderpumpe 12 and the high-pressure pump 14, a volume flow control valve 20 is further arranged, which allows a low-pressure side control of the fuel flow, which is to be supplied to the high-pressure pump 14. For this purpose, the volume flow control valve 20 can be controlled as a function of a fuel pressure measured in the fuel reservoir 16, which is determined by a pressure sensor 24, as well as in dependence on further input variables.

Between the Vorforderpumpe 12 and the admission pressure control valve 28 branches off from a Spulleitung 30, the mouth side tastes in the housing of the high-pressure pump 14. Thus, during operation of the high-pressure pump 14, the housing of the high-pressure pump 14 can be wound, whereby cooling and lubrication of the high-pressure pump 14 is made possible. In the Spulleitung 30 a Spulleitungsventil 32 and hydraulically in series a Spulleitungsdrossel 34 is arranged. The Spulleitungsdrossel 34 serves to limit the diverted to Spulungszwecken in the Spulleitung 30 Kraftstoffström. The Spulleitungsventil 32 is designed so that it releases the current flowing through the Spulleitung 30 Brennstoffström only when exceeding a planned fuel pressure of the output side of the Vorforderpumpe 12. The opening pressure at the Spulleitungsventil 32 must be greater than the opening pressure of the intake valves (not shown) of the high-pressure pump 14 and the intervening line. This is the only way to ensure that the winding of the high pressure pump 14 is only used when the operating pressure of the high pressure pump 14 is reached. This ensures that the pressure build-up on the suction side of the high pressure pump 14 is not delayed. The fuel used for Spulungs- purposes can leave the high-pressure pump 14 via a Spulrucklaufleitung 35 and be returned via this in the fuel tank 10.

Preferably, filters 36, 38 are arranged in front of the front-end pump 12 and the volume flow control valve 20 for protection against particles entrained in the fuel flow or for separating water. Thus, to protect the Vorforderpumpe 12 hydraulically between the fuel tank 10 and the Vorforderpumpe 12, a first filter 36 is provided. Furthermore, a second filter 38 is arranged in front of the volume flow control valve 20 to protect the volume flow control valve 20 and the high-pressure pump 14.

The valve 22 is branched off in the downstream of the high-pressure pump 14 and upstream of the fuel reservoir 16

Line 42 is arranged, the output side of which is coupled to an injector return line 46 of the at least one injector 18. The Spulrucklaufleitung 35, the branching line 42 and the Injektorrucklaufleitung 46 of the injectors 18 are preferably returned to the fuel tank 10.

FIG. 2 shows in detail a first embodiment of the valve 22 which is arranged between the fuel storage supply line 44 and the branching line 42 downstream of the high-pressure pump 14.

The valve 22 has a valve housing 50 with a longitudinal axis X. In the valve housing 50 a Ventilgehauseausnehmung 52 is formed. Upstream of the valve housing recess 52 is a fluid inlet opening 54 and downstream of the valve housing. Tilgehauseausnehmung 52 a Fluidaustrittsoffnung 56 is arranged. The fluid inlet opening 54 and the fluid outlet opening 56 can be hydraulically coupled to the valve housing recess 52. In the Ventilgehauseausnehmung 52 between the Fluideintrittsoffnung 54 and the Fluidaustrittsoffnung 56 a Ventilkorper 58 is arranged, which is axially movable in the Ventilgehauseausnehmung 52. By means of a spring element 60, the valve body 58 can be acted upon by force in the direction of the fluid inlet opening 54. The valve housing recess 52 has a wall 66 on which a first sealing seat 62 and a second sealing seat 64 are formed.

The valve body 58 has a first seat area 68 in a lower section with reference to FIG. 2 and a second seat area 70 with an upper section with respect to FIG. 2.

Both the first sealing seat 62 and the second sealing seat 64 of the wall 66 of the valve housing recess 52 as well as the first seating area 68 and the second seating area 70 of the valve body 58 are conically formed in the embodiment shown here.

The first sealing seat 62 of the wall 66 of the valve housing recess 52 and the first seat portion 68 of the Ventilkorpers 58 may cooperate such that a fluid flow between the Fluideintrittsoffnung 54 and the Fluidaustrittsoffnung 56 is interrupted. Likewise, the second sealing seat 64 on the wall 66 of the Ventilgehauseausnehmung 52 so cooperate with the second seat portion 70 of the Ventilkorpers 58 that a flow of fluid from the Fluideintrittsoffnung 54 is prevented to the Fluidaustrittsoffnung 56. In a starting position in which the fluid pressure at the fluid inlet opening 54 assumes only a small value, the valve body 58 is pressed by the spring force of the spring element 60 against the wall 66 of the valve housing recess 52 such that the first Sealing seat 62 of the wall 66 of the Ventilgehauseausnehmung 52 and the first seat portion 68 of Ventilkorpers 58 sealingly prevent fluid throughput through the Fluidaustrittsoffnung 56.

The first sealing seat 62 of the wall 66 of the valve housing recess 52 has a first cone opening angle ALPHA 1. The second sealing seat 64 of the wall 66 of the valve housing recess 52 has a second cone opening angle ALPHA_2, and the second cone opening angle ALPHA_2 of the second sealing seat 64 of the wall 66 is smaller than the first Cone opening angle ALPHA_1 of the first sealing seat 62 of the wall 66.

The cone-shaped first seating area 68 of the valve body 58 has a first cone opening angle BETA_1, and the second seating area 70 of the valve body 58 has a second cone opening angle BETA 2. The first cone opening angle BETA 1 of the first seating area 68 of the valve body 58 is smaller than the second cone opening angle BETA 2 the second seating area of the valve body 58.

FIG. 3 a shows the course of an effective throttle area A of the valve 22 as a function of a fluid pressure P at the fluid inlet opening 54.

In a first region of the fluid pressure P below a first fluid pressure value P_1, the first sealing seat 62 of the wall 66 of the valve housing recess 52 bears against the first seat region 68 of the valve body 58. The effective throttle area A is therefore zero in this area.

In a second region of the fluid pressure P at the fluid inlet opening 54 above a second fluid pressure value P 2, the second seat region 70 of the valve body 58 rests against the second sealing seat 64 of the wall 66 of the valve housing outlet. mung 52 and the effective throttle area A of the valve 22 is equal to zero.

In a third region of the fluid pressure P at the fluid inlet opening 54 above the first fluid pressure value P 1 and below the second fluid pressure value P 2, the effective throttle area A first increases from zero to a maximum effective throttle area A_MAX. In a further increase of the fluid pressure P at the fluid inlet opening 54 to a third fluid pressure value P_3, the effective throttle area A is initially equal to the maximum effective throttle area A_MAX. Finally, the second seating area 70 of the valve body 58 approximates the second sealing seat 64 of the wall 66 of the valve housing recess 52 such that the effective throttle area A continuously decreases until it finally becomes zero for the second fluid pressure value P 2.

Since the first cone opening angle ALPHA 1 of the first sealing bit 62 of the wall 66 of the valve housing recess 52 is greater than the second cone opening angle ALPHA 2 of the second sealing seat 64 of the wall 66 of the valve housing recess 52 or the first cone opening angle BETA_1 of the first seating area 68 of the valve body 58 is smaller As the second cone opening angle BETA_2 of the second seat portion 70 of the valve body 58, it can be easily achieved that an increase in the effective throttle area A occurs when passing through a small fluid pressure area and a reduction in the effective throttle area A is possible when passing through a large fluid pressure area.

FIG. 3b shows a profile of a fluid flow rate FR as a function of the fluid pressure value P. According to the course of the effective throttle area A, in the first region of the fluid pressure P at the fluid inlet opening 54 below the first fluid pressure value P 1, the fluid flow through the fluid outlet opening 56 is prevented, so that the fluid flow rate FR is equal to zero here.

In the second region of the fluid pressure P at the fluid inlet opening 54 above the second fluid pressure value P_2, the fluid throughput through the fluid outlet opening 56 is likewise prevented, a first fluid throughput value FR_1 equal to zero is reached.

In the third region of the fluid pressure at the fluid inlet opening 54 above the first fluid pressure value P_l and below the second fluid pressure value P_2, a fluid throughput through the fluid outlet opening 56 is provided. The fluid throughput increases in a fourth range of the fluid pressure at the fluid inlet opening 54 above the first fluid pressure value P 1 and below a third fluid pressure value P 3 initially from zero to a second fluid flow rate FR 2. In a fifth region of the fluid pressure at the fluid inlet opening 54 above the third fluid pressure value P 3 and below the second fluid pressure value P_ 2, the fluid flow rate FR through the fluid outlet opening 56 finally decreases again from the maximum second fluid flow value FR_ 2 to zero.

Since the first cone opening angle ALPHA_1 of the first sealing seat 62 is greater than the second cone opening angle ALPHA_2 of the second sealing seat 64 and the first cone opening angle BETA 1 of the first seating area 68 is smaller than the second cone opening angle BETA 2 of the second seating area 70 of the valve body 58, it is achieved that the fluid flow rate in a small fluid pressure range increases from zero to the second fluid flow rate value FR 2, while Fluid flow rate FR falls in a large fluid pressure range from the second fluid flow rate FR 2 to the first fluid flow rate FR_1 (equal to zero).

In Figure 4, the valve 22 is shown in a second embodiment. The valve 22 of the second embodiment differs from the valve 22 of the first embodiment in that the Ventilkorper 58 in its Fluidaustritts- opening 56 facing region has a cylinder portion 72 having a cylindrical portion 74 of the wall 66 of the Ventilgehauseausnehmung 52 to form a gap 76 corresponds, wherein a gap length L of the gap 76 is variable.

As can be seen in FIG. 5a, the gap length L increases continuously as the fluid pressure P between the first fluid pressure value P 1 and the second fluid pressure value P 2 increases, from a minimum gap length L MIN to a maximum gap length L MAX. Above the second fluid pressure value P 2, the gap length L remains constant at the maximum gap length L_MAX.

Since, below the first fluid pressure value P_1, the first seat region 68 of the valve body 58 bears against the first sealing seat 62 of the wall 66 of the valve housing recess 52, the fluid flow rate FR is equal to zero (FIG. 5b). By despatching the first seat portion 68 of the valve body 58 from the first sealing seat 62 of the wall 66 of the valve housing recess 52 for the first fluid pressure value P_l, the fluid flow rate from zero to the second fluid flow rate value FR 2 increases. Finally, until the second fluid pressure value P 2 is reached, the fluid flow rate FR drops continuously from the second fluid flow rate value FR 2 to the first fluid flow rate value FR 1. This is possible by controlling the fluid flow rate FR over the gap length L between the minimum gap length L MIN up to the maximum gap length L MAX.

If the fluid pressure P is greater than the second fluid pressure value P_2, it is achieved that, by leaving the gap length L at the maximum gap length L MAX and the absence of the second sealing seat 64 of the wall 66, the fluid flow rate substantially assumes the constant first fluid flow rate value FR_1.

The following briefly describes the mode of operation of the injection system:

The pre-demand pump 12 requires fuel from the fuel tank 10. By means of the admission pressure control valve 28, the pressure of the fuel to be supplied to the high-pressure pump 14 is limited. The precharge pump 12 supplies the fuel via the second filter 38 to the volume flow control valve 20. At this, the fuel flow rate for the suction side of the high-pressure pump 14 can be adjusted. The high-pressure pump 14 supplies the fuel reservoir 16 via the fuel storage line 44 with the amount of fuel required for the injectors 18. The pressure required for the fuel reservoir 16 can first be adjusted by means of the pressure sensor 24 via a volume flow control on the volume flow control valve 20. In a low and middle region of the fluid pressure, that is to say in the first and third regions of the fluid pressure at the fluid inlet opening 54, however, a fluid leakage flow can occur at the volume flow control valve 20. In particular, in the third region of the fluid pressure at the Fluideintrittsoffnung 54, the valve 22 each open so far that this leakage fluid flow via the downstream of the high-pressure pump 14 and upstream of the fuel reservoir 16 branching line 42 can flow into the fuel tank 10, together with the fluid from the Spulrucklauf- line 35 and the effluent via the Injektorrucklaufleitung 46 from the injectors 18 fluid.

It is particularly advantageous if the fluid flow rate FR continuously decreases in the largest possible portion of the third area of the fluid pressure at the fluid inlet opening 54 above the first fluid pressure value P 1 and below the second fluid pressure value P_2, since in this case the valve 22 is particularly good Control characteristic with respect to a occurring in the third region of the fluid pressure at the Fluideintrittsoffnung 54 above the first fluid pressure value P_l and below the second fluid pressure value P_2 fluid leakage flow through the flow control valve 20 of the injection system has. It is thus possible with the aid of the valve 22 to dissipate the fluid leakage flow occurring at the volume flow control valve 20 in a particularly simple manner via the branching line 42 to the fuel tank 10. Since the fluid leakage flow occurring at the volume flow control valve 20 with increasing fluid pressure P has an ever smaller influence on the control quality of the control loop of the flow control valve 20, it is advantageous if the fluid flow rate FR through the valve 22 in a large portion of the third region of the fluid pressure P at the Fluideintrittsoffnung 54 above the first fluid pressure value P_l and below the second fluid pressure value P_2 continuously decreases from the second fluid flow rate FR_2 to the small first fluid flow rate FR_1.

In the first region of the fluid pressure at the fluid inlet opening 54 below the first fluid pressure value P 1, the fluid flow rate FR through the valve 22 and thus via the branching line 42 is prevented in order to allow an undisturbed starting of the injection system. In the second area of the fluid pressure at the fluid inlet opening 54 above the second fluid pressure value P 2, the fluid flow rate FR through the valve 22 is likewise prevented or restricted to the small fluid flow rate value FR 1 in order to keep the fluid leakage flow rate via the branching line 42 small , as this is always associated with a loss of energy at the injection system. These losses can be effectively kept small with the illustrated valve 22 for the entire operation of the injection system.

The volume flow control valve 20 is thus over the entire control range, the active actuator to be set. On multiple control circuits with different pressure-dependent actuators can be dispensed with. In particular, it is possible to dispense with a separate control circuit with a pressure control valve. For a simple and yet precise control of the injection system is possible.

Claims

Patent claims

1 . Venti l (22), with

- A valve housing (50) having a longitudinal axis (X) having a Ventilgehauseausnehmung (52) with a wall (66),

a fluid inlet opening (54) and a fluid outlet opening (56) which are arranged in the valve housing (50) and can be hydraulically coupled to the valve housing recess (52), - a sealing seat formed on the wall (66) of the valve housing recess (52) ( 62, 64),

a valve body (58) arranged axially movably in the valve housing recess (52) between the fluid inlet opening (54) and the fluid outlet opening (56) and having a seating area (68, 70) which cooperates with the sealing seat (62, 64) that in a closed position, a fluid flow through the Fluidaustrittsoffnung (56) prevents and otherwise the fluid flow through the Fluidaustrittsoffnung (56) is released, - and a spring element (60) through which the Ventilkorper (58) in the direction of the Fluideintrittsoffnung (54) with force can be acted upon, wherein the Ventilkorper (58) and the spring element (60) are formed and arranged so that in a first region of the fluid pressure at the Fluideintrittsoffnung (54) below a first fluid pressure value (P_l) prevents the fluid flow through the Fluidaustrittsoffnung (56) in that in a second region of the fluid pressure at the fluid inlet opening (54) above a second fluid pressure value (P_2) a fluid d flow rate through the fluid exit port (56) having a maximum first fluid flow rate (FR 1), and that in a third range of fluid pressure at the fluid inlet port (54) above the first fluid pressure value (P 1) and below the second fluid pressure value (P 2) a fluid flow through the Fluidaustrittsoffnung (56) with a maximum second fluid flow rate (FR 2) is allowed to be greater than the first fluid flow rate value (FR_1).

2. Valve (22) according to claim 1, that the Ventilkorper (58) and the sealing seat (62, 64) are formed and arranged so that in a fourth region of the fluid pressure at the Fluideintrittsoffnung (54) above the first Fluiddruck- value ( P_l) and below a third fluid pressure value (P_3), a variation of the fluid flow through the Fluidaustritts- soffnung (56) between zero and the maximum second fluid flow rate (FR_2) is possible, and in a fifth range of fluid pressure at the Fluideintrittsoffnung (54) above the third fluid pressure value (P_3) and below the second fluid pressure value (P_2) a variation of the fluid flow rate through the Fluidaustrittsoffnung (56) between the maximum second fluid flow rate (FR 2) and the maximum first fluid flow rate (FR 1) is possible, wherein the fourth range the fluid pressure at the fluid inlet port (54) is less than the fifth range of the fluid pressure at the fluid inlet port (54).

3. Valve (22) according to claim 1 or 2, with a on the wall (66) of the Ventilgehauseausnehmung (52) formed first sealing seat (62) and on the wall (66) of the Ventilgehauseausnehmung (52) formed second sealing seat (64). axially spaced from the first sealing seat (62), the valve body (58) being disposed axially between the first sealing seat (62) and the second sealing seat (64), and the valve body (58) having a first seating area (68) cooperating with the first sealing seat (62) such that in the first region of the fluid pressure at the fluid inlet opening (54) below the first fluid pressure value (P 1) a fluid flow through the fluid outlet opening (56) is prevented, and the valve body (58) has a second seating area (70) cooperating with the second sealing seat (64) such that in the second range of fluid pressure at the fluid inlet port (54) above the second fluid pressure value (P 2) a fluid flow rate is prevented by the Fluidaustrittsoffnung (56).

4. Valve (22) according to claim 3, wherein the first sealing seat (62) konusformig formed with a first Kegeloff- angle (ALPHA_1) and the second sealing seat (64) konusformig is formed with a second Kegeloffnungswinkel (ALPHA_2), and the first Cone opening angle (ALPHA_1) of the first sealing seat (62) is greater than the second cone opening angle (ALPHA_2) of the second sealing seat (64).

5. Valve (22) according to claim 3 or 4, wherein the first seating area (68) of the Ventilkorpers (58) is konusformig formed with a first cone opening angle (BETA 1) and the second seating area (70) of the Ventilkorpers (58) is konusformig with a second cone opening angle

(BETA_2), and the first cone opening angle (BETA_1) of the first seat portion (68) is smaller than the second cone opening angle (BETA_2) of the second seat portion (70).

The valve (22) according to claim 1 or 2, wherein the valve body (58) has a cylinder portion (72), and the wall (66) of the valve housing recess (52) has a cylinder portion (74) and the valve body (58) is so in the valve housing recess (52), a gap (76) with a gap length (L) is arranged between the cylinder section (72) of the valve body (58) and the cylinder section (74) of the wall (66) of the valve housing recess (52). is formed such that in the third region of the fluid pressure at the Fluideintritts- soffnung (54) above the first fluid pressure value (P 1) and below the second fluid pressure value (P 2), the gap length (L) is variable as a function of the fluid pressure at the fluid inlet opening (54), wherein a minimum gap length value (L MIN) for the first fluid pressure value (P 1) and a maximum slit limit for the second fluid pressure value (P 2). gen value (L MAX) is assumed.

7. injection system for an internal combustion engine, with

at least one injector (18) coupled to a fuel reservoir (16), - a pre-demand pump (12) for requesting fuel from a fuel tank (10),

- One of the Vorforderpumpe (12) downstream downstream high-pressure pump (14) for demand of the fuel in the fuel reservoir (16), - one of the high-pressure pump (14) downstream downstream valve (22) according to one of the preceding claims, with which in the fuel storage ( 10) to be produced pressure is adjustable.

8. Injection system according to claim 7, wherein hydraulically between the Vorforderpumpe (12) and the high-pressure pump (14) a flow control valve (20) is arranged, with which the fuel flow from the Vorforderpumpe (12) in the high-pressure pump (14) is adjustable.