DE102007026834A1 - Electromagnetic control valve e.g. for internal combustion engine, has valve unit, full valve casing, inlet port, consumer connection and piston valve which is relocatable compared with valve casing - Google Patents

Abstract

The electromagnetic valve (1) has a valve unit (10), a full valve casing (101), an inlet port (102), a consumer connection (103) and a piston valve (104), which is relocatable compared with the valve casing (101). A valve seat (100) has a piston seat (105) arranged between the inlet port (102) and consumer connection (103) and has valves (104) which front face a closing element (106). The valve piston (104) is arranged on the inlet side (110). An independent claim is included for an injection unit.

Description

The The invention relates to electromagnetic control valve according to the The preamble of claim 1 and an injection system for an internal combustion engine according to the preamble of claim 8.

at a common-rail injection system is the fuel of a High pressure pump pumped into a fuel tank and over Injectors injected into the combustion chamber of the internal combustion engine. For internal combustion engines with direct injection must hereby high fuel pressures already exist in the start phase, to achieve sufficient mixture preparation to ignite the To allow mixture. The minimum fuel pressure is for direct-injection gasoline engines approx. 50 bar and for direct-injection Diesel engines approx. 120 bar. Such pressures become two-stage by means of a prefeed pump and a usually of a sitting on the camshaft high pressure pump. In order to the minimum fuel injection pressure available early can be put, from the practice is also the use of electrically controllable high-pressure pumps known.

From the high-pressure pump considered downstream closes in an operating according to the common rail principle internal combustion engine for Fuel delivery in addition to a rail and a plurality on injectors, in the high pressure area a fuel tank. excess Pressure is from the fuel tank via a return line to the Fuel tank degraded, with the control often electric controlled PCV pressure valves are used.

In the publication DE 199 37 673 A1 Such an injection system for an internal combustion engine is described. The injection system is configured with a prefeed pump for conveying fuel from a fuel tank, a downstream of the feed pump high-pressure pump for generating the required injection of fuel into a combustion chamber of the engine injection pressure, arranged between the prefeed pump and the high-pressure pump flow control valve for controlling the high-pressure pump supplied fuel flow. The volume flow control valve is controllable between an open position and an at least partially closed position and configured in connection with the prefeed pump, that the fuel flow through the flow control valve in the open position of the flow control valve is substantially equal to the maximum fuel demand of the injection system to an excess fuel supply to avoid the high pressure pump.

In the publication EP 1 109 999 B1 A method for quickly building up the fuel pressure in a fuel storage is described. For this purpose, a high pressure pump for pressurizing promotes fuel in the fuel tank, the pump chamber is only partially filled with fuel in some operating conditions. During the shutdown of the fuel supply to the high pressure pump is controlled so that the pump cylinders are filled to a standstill of the engine and the high pressure pump to provide a largely or completely filled pump room in the subsequent startup regardless of the operating state of the previous shutdown of the high pressure pump. A high-pressure pump reaches its maximum delivery capacity with a filled pump chamber, whereby a fast pressure build-up in the fuel accumulator is advantageously achieved at the start. To control a controllable valve between the prefeed pump and the high-pressure pump is proposed, which is designed either as a slide valve or a poppet valve, which is normally open depending on the embodiment (a so-called "NO") or closed (a so-called "opener"). As seat valve, a digitally switchable valve is proposed, which only temporarily opens or closes during the duration of a suction process of the high-pressure pump.

Furthermore, from the document DE 10 2004 057 873 A1 a seat valve with a conduit system for passing a medium, which flows on an inflow side. The seat valve has a seat in the piping system and an adjustable closing element for at least partially closing and opening the conduit system for the medium. An adjusting device serves to close the closing element, wherein the adjusting device usually has a coil and an armature. The closing element is used in the unactuated state of the adjusting device for closing the conduit system. It is in construction to a normally closed seat valve, which can control a proportional flow or pressure. In such a design of a poppet valve, the proportional solenoid, which is formed by the coil and armature assembly, operates against the pressure. By a compression spring such poppet valves are normally closed. As a special embodiment, the closing element is spherical. However, the fuel flow must be passed before the poppet valve consuming the leadership of the ball.

Of the Invention is based on the object, an electromagnetic control valve and associated therewith, an injection system for an internal combustion engine educate so that the fluid flow in a pressurized Seat valve can be reliably controlled.

The Invention is with respect to the electromagnetic control valve by the features of claim 1 and with regard to the injection system for an internal combustion engine by the features of the claim 8 reproduced. The other related claims relate to advantageous embodiments and further developments of the invention.

The The invention includes an electromagnetic control valve a, with a valve unit, comprising a valve housing, at least one inlet connection, at least one consumer connection and a spool, which is opposite the valve body is displaceable and with an actuator, comprising at least an electromagnetic coil, a sliding armature and an axial arranged plunger, wherein the sliding armature via the axially arranged plunger with the spool axially in operative connection. According to the invention a seat valve with a piston seat between inlet port and Arranged consumer connection and the spool on his the piston seat facing end a closing element educated. Furthermore, the spool is on the inlet side arranged.

The Control valve thus has a movable in its valve housing guided piston slide, by means of the actuator is adjustable in its position in the axial direction. The respective Control position of the piston valve is by a corresponding current supply the electromagnetic coil continuously variable.

The Control valve according to the invention is in operation as an opener used and is thus closed without leakage in the de-energized state. The force required to open the seat valve is decisive for the sizing of the whole Adjusting unit. The smaller the pressurized area the seat valve is designed, the smaller the can Building components of the actuator even with larger Fluid pressures are dimensioned at the inlet connection. Indeed the passage area of the piston seat must be sufficient be dimensioned to promote enough fluid.

Of the Piston seat can be a deep drawn sleeve with central Be bore. The hole can be stamped accordingly be in order to interact with the closing element on the Front side of the spool valve in the closed state, the tightness to ensure. The freedom from leakage is preferred over achieved a bias of the piston, for example via a coil spring.

One particular advantage is that by the inventive Solution a simple and reliable sealing principle is available. By using the piston valve in conjunction with the piston seat is a linear Q-I characteristic available for tax. The linearity of Characteristic is among other things by the particularly advantageous concentric opening cross-section between the piston seat bore and the preferably conical end face condition of the Kobenschiebers. Here is the term linearity to the effect that, apart from a starting area, an increase in the electric control current the flow rate in proportional relationship increased. Between the I-ratio and the Q ratio is according to this embodiment a direct mathematical relationship that has a direct Characteristic curve can be reproduced. The characteristic looks like a branch of a parabola.

Of the Fluid flow can thus via the control edge with the spool reliably controlled and without disturbing pressure surges be managed. In particular, there is a very significant advantage in that the control valve in the de-energized state is leak-free. As a result, for example, in a common rail injection system other components much easier and thus designed more cost-effective become. Also, in such systems in the inventive leak-free control valve, an engine shutdown without additional effort safely guaranteed.

In an advantageous embodiment of the invention can on the inlet side at least one inlet connection between piston valve and piston seat and at least one further inlet port on the The piston seat facing away from the piston seat arranged be. In other words, through several inlet connections On the inlet side, on the one hand, the required amount of fluid provided close to the seat valve and on the other hand the Piston slide on its back, so the piston seat opposite side, pressurized with fluid pressure. It follows a resultant force to control the poppet valve from the balance the pressure distribution of the fluid on the front and back of the piston valve. Because on the front through the open Seating valve fluid flows out, standing in front of the seat valve a pressure drop. On the other hand, exercises on the back the fluid is a static pressure. From this balance emerges on the spool a certain overpressure on the back, whereby from fluid mechanical considerations a resulting force push the piston towards the piston seat and thus tend to close. This However, resulting from the pressure difference force acts the actuator opposite, in the energized state with a linear I-Q characteristic activates the valve. Here it becomes clear that the dimensioning the actuator comparatively small and therefore cost can fail.

Especially It is advantageous if the control edge located on the spool valve the seat valve is conical or spherical. This will affect the flow conditions of the Fluids favorable effect symmetry of the closing element used. Conical or otherwise symmetrical shapes can unfold centering effect.

advantageously, can the seat valve in the de-energized state of the actuator through a force acting in the closing direction on the spool be closed elastic element, which is against the inner wall the valve housing is supported. The elastic element is designed and arranged so that primarily in the longitudinal direction act on the spool axial forces. This will the seat valve in the de-energized state of the actuator, for example through a on the rear face of the Piston slider acting coil spring closed, which is is supported against the inner wall of the valve housing. The spring exerts a force on the spool, the counteracts the force of the ram and in the de-energized state a defined closed state causes.

Prefers can the plunger of the actuator by the piston seat be arranged against the closing element. Out the axially directed application of force of the plunger on the piston valve, the closing element without disturbing Transverse forces controllable.

advantageously, is the pestle in the section where he is passes through the piston seat, relative to the opening the piston seat is formed so that the fluid in the open Valve condition can flow through sufficiently. about Dimensioning of the ram in this section in particular, the maximum possible Influencing and defining the volume flow through the seat valve.

In A further advantageous development of the plunger in the section where it passes through the piston seat, be designed so that it has an additional control function the fluid flow occupies. This can be immediate or in advance the piston seat acting thickening of a portion of the plunger be, with which the volume flow can be selectively limited. Hereby leave Above all, large flow rates are advantageous and limit upwards.

One Another aspect of the invention includes an injection system for an internal combustion engine, at least with a prefeed pump for conveying fuel from a fuel tank, with a downstream of the pre-pump downstream high-pressure pump for generating the fuel for injection into one Combustion chamber of the engine required injection pressure and with a flow control valve. The flow control valve consists of valve unit and actuator for controlling the High pressure pump fuel flow and is between the prefeed pump and the high-pressure pump arranged. The the valve unit has at least one valve housing, one Inlet connection, a consumer connection and a spool valve on, which is displaceable relative to the valve housing is. The actuating unit has at least one electromagnetic coil, a slidable armature and an axial ram on, wherein the displaceable armature over the axially arranged Plunger with the spool in operative connection stands. According to the invention, a seat valve with a piston seat between inlet port and consumer port arranged and facing the spool on his the piston seat End face formed a closing element. In addition, the Piston slide arranged on the inlet side.

hereby can in a common-rail injection system other components much easier and thus be designed more cost-effective. Also, in such systems in the inventive Solution by the absence of leakage an engine shutdown Safely guaranteed without extra effort.

in the Normally, the high-pressure pump can pump significantly more fuel, as needed in the engine. To a surplus To avoid fuel flow, advantageously, the poppet valve the maximum available in the high pressure pump Limit fuel flow and adjust. This is possible especially with the plunger of the actuator simple realize, through the piston seat through the spool regulated with its front-side closing element. For this is the diameter of the plunger in the section, in which it passes through the piston seat to the maximum required Fuel quantity designed. In addition, also the diameter be selected according to the piston seat. It is the low-pressure side control of the maximum fuel flow through the Control valve according to the invention substantially more advantageous opposite the otherwise required high-pressure side Control with a controllable high pressure valve. Unfavorable in a high pressure side control is that excess heated fuel returned to the fuel tank must become. By this configuration is low pressure side already ensuring a limitation of the maximum fuel flow, the depends on the fuel requirements of the injection system.

In a further preferred embodiment of the invention, the high pressure pump downstream arranged downstream of a high pressure valve for pressure control without external control. Only through the solution according to the invention does the potential in a common-rail injection system result in considerably simpler and thus more cost-saving design of other components.

All further advantageous embodiments described above with respect to designed as a flow control valve electromagnetic control valve can in the same way find application in the injection system.

The Invention is achieved by further preferred embodiments explained in more detail with reference to the schematic drawing.

In this demonstrate:

1 an electromagnetic control valve in cross-section,

2 a detail of the control valve in the valve unit,

3 a diagram of the QI characteristic of the control valve, and

4 an injection system for an internal combustion engine.

each other corresponding parts are provided with the same reference numerals.

1 shows an electromagnetic control valve 1 , designed as a flow control valve, with a valve unit 10 and an actuator 20 in cross section. The valve unit 10 includes a valve housing 101 , one inlet connection (P connection) 102 , one consumer connection (A connection) 103 and a piston valve 104 , opposite the valve body 101 is displaceable.

A detail of the control valve 1 in the area of the valve unit 10 is in 2 shown. Between inlet connection 102 and consumer connection 103 is a seat valve 100 with a piston seat 105 arranged, wherein the spool 104 on his the piston seat 105 facing end a closing element 106 , here in the form of a truncated cone, is formed. The piston seat 105 is one in the valve body 101 arranged sleeve with central bore, which is stamped to in the closed state in interaction with the closing element 106 to ensure the required tightness. By embossing is also the respective control edge 107 on the piston seat 105 and on the closing element 106 designed advantageous.

The piston valve 104 is on the inlet side 110 arranged. On the inlet side 110 are opposite two inlet connections 102 between piston valve 104 and piston seat 105 arranged, through which the fluid into the volume flow valve 1 flows. According to a further embodiment, more than just two inlet connections, namely three or four, can be arranged in a row distributed at the same height. In addition, there is another inlet connection 102 on the piston seat 105 opposite side, so the back of the piston valve 104 arranged.

The piston valve 104 This is also applied to its rear side with fluid pressure. These P-connections are supplied via a not shown in the figures, branching supply. By a fluid removal via an open during operation seat valve 100 arises in relation to the static fluid pressure on the back of the piston valve 104 a pressure difference and thus a resulting force, which tends to the spool 104 in the direction of the piston seat 105 suppressed. How out 1 however, this force resulting from the pressure difference acts as the actuator 20 contrary, in the energized state, the seat valve 100 controls.

However, regardless of the fluid pressure, the seat valve 100 in the de-energized state of the actuator 20 Safe to close, is a closing direction on the piston valve 104 acting elastic element 108 arranged in the form of a coil spring, which is against the inner wall of the valve housing 101 on a spring plate 109 supported.

According to this from the different pressure ratios in the valve and the coil spring 104 resulting force distribution is ultimately the control characteristic of the actuator 20 interpreted. The actuator 20 includes according to 1 an electromagnetic coil 201 with a sliding anchor 202 that's about the pestle 203 with the piston valve 104 interacts. The pestle 203 is on the drain side 111 the valve unit 10 arranged and acts through the piston seat 105 through against the closing element 106 , From the axially directed application of force of the plunger 203 on the front side of the valve housing 101 with little clearance guided piston valve 104 becomes the closing element 106 reliably controlled without disturbing shear forces.

At the actuator 20 is the electromagnetic coil 201 with a sliding anchor 202 in a housing 204 integrated with the actuating unit. The valve cover closes at the rear 205 with the lid gasket 210 the actuator 20 , A sleeve 206 serves to separate the hydraulic space from the magnet and thus limits the area in the fluid can penetrate. To the valve part 10 in this regard, the hydraulic bushing seal 211 between sleeve 206 and valve unit 10 arranged. The anchor 202 is with an anchor bearing bush 207 slidably mounted for axial movement, which may also be referred to as prone. Between anchor 202 and pestles 203 is still a spacer for power transmission 208 involved. The valve mounting flange 209 lies in a connecting manner between the valve unit 10 with the actuator 20 , Another valve seal 212 is arranged on the storage area.

Between A port and P port is a hydraulic seal 213 integrated, which the inlet side 110 and the drain page 111 seals against each other.

3 shows a diagram of the QI characteristic of the control valve according to the invention 1 , Due to the design of the piston valve 104 in conjunction with the piston seat 105 results in a linear course of a QI characteristic for controlling. More precisely, the course is like a branch of a second-degree elongated parabola. Will the control valve 1 energized, so at low currents up to about 0.5 A is the seat valve 100 still securely closed. The from the actuator 20 at low currents available power is not enough to counteract the resulting fluid pressure and acting in the same direction helical compression spring 108 to open the seat valve. Only from a current of more than 0.5 A on the piston valve 104 applied force of the plunger 203 sufficient to the closing element from the piston seat 105 move away. From this current, fuel is passed from the prefeed pump to the downstream downstream high-pressure pump in a common-rail injection system.

4 shows an injection system for an internal combustion engine with a prefeed pump 3 for pumping fuel from a fuel tank 2 and with one of the prefeed pump 3 downstream downstream high-pressure pump 4 for generating the injection pressure required for injecting the fuel into an engine. The flow control valve 1 with valve and actuator, which is located between the pre-feed pump 3 and the high pressure pump 4 is arranged, controls the high-pressure pump 4 supplied fuel flow. In such a common rail injection system, other components can be designed much easier and more cost-effective. Such is the high pressure pump 4 downstream of a high pressure valve 5 downstream of the pressure control, which manages without external control.

The admission valve 6 serves for pressure control of the pre-pressure area and is downstream of the pre-feed pump 3 downstream. If a predetermined maximum admission pressure is exceeded, then via the admission pressure valve 6 a portion of the amount of fuel to the suction side of the feed pump 3 recycled. The admission valve 6 is also configured without external control as a differential pressure valve.

On the output side is the high-pressure pump 4 with the high-pressure accumulator 7 connected, from which the injectors 8th be fueled. The injectors 8th and the flow control valve 1 are controlled by an electronic control unit ECU. In the illustrated high-pressure side control must in conjunction with the volume flow control valve according to the invention 1 only a small proportion of excess fuel in the fuel tank 2 be returned because low pressure side already a limitation of the maximum fuel flow is ensured, which depends on the fuel requirements of the entire injection system.

1

electromagnetic Control valve, flow control valve

10

valve unit

100

poppet valve

101

valve housing

102

Inlet connection, P port

103

Consumer connection, O port

104

spool

105

piston seat

106

closing element

107

control edge

108

elastic Element, valve seat spring, helical compression spring

109

spring plate

110

supply side

111

outlet side

20

actuator

201

Kitchen sink

202

anchor

203

tappet

204

casing the actuator

205

valve cover

206

sleeve, in particular for the separation of the hydraulic space from the magnet

207

Anchor bush

208

spacer

209

Ventilbefestigungsflansch

210

cover gasket

211

Hydraulic jack seal

212

Valve seal, especially on the storage area

213

Hydraulic seal, especially between A-port and P-port

2

Fuel tank

3

prefeed

4

high pressure pump

5

High pressure valve

6

form valve

7

High-pressure accumulator

8th

injectors

ECU

electronic control unit

arrow A

O port

arrow P

P port

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 19937673 A1 [0004]
• - EP 1109999 B1 [0005]
• - DE 102004057873 A1 [0006]

Claims (11)

Electromagnetic control valve ( 1 ), with a valve unit ( 10 ), comprising a valve housing ( 101 ), at least one inlet connection ( 102 ), at least one consumer connection ( 103 ) and a piston valve ( 104 ), opposite the valve housing ( 101 ) is displaceable, - with an actuating unit ( 20 ) comprising at least one electromagnetic coil ( 201 ), a sliding anchor ( 202 ) and an axially arranged plunger ( 203 ), wherein the displaceable anchor ( 202 ) over the axially arranged plunger ( 203 ) with the piston valve ( 104 ) is axially in operative connection, characterized in that - a seat valve ( 100 ) with a piston seat ( 105 ) between inlet connection ( 102 ) and consumer connection ( 103 ) is arranged and on the piston valve ( 104 ) on its the piston seat ( 105 ) facing a closing element ( 106 ), and - that the piston valve ( 104 ) on the inlet side ( 110 ) is arranged. Electromagnetic control valve according to claim 1, characterized in that on the inlet side ( 110 ) at least one inlet connection ( 102 ) between piston valve ( 104 ) and piston seat ( 105 ) and at least one further inlet connection ( 102 ) on the piston seat ( 105 ) facing away from the piston valve ( 104 ) is arranged. Electromagnetic control valve according to claim 1 or 2, characterized in that the piston slide ( 104 ) located control edge ( 107 ) of the seat valve ( 100 ) is conical or spherical. Electromagnetic control valve according to one of claims 1 to 3, characterized in that the seat valve ( 100 ) in the de-energized state of the actuator ( 20 ) by a closing direction on the spool ( 104 ) acting elastic element ( 108 ) is closed, which is against the inner wall of the valve housing ( 101 ) is supported. Electromagnetic control valve according to one of claims 1 to 4, characterized in that the plunger ( 203 ) of the actuator ( 20 ) through the piston seat ( 105 ) through against the closing element ( 106 ) is arranged. Electromagnetic control valve according to claim 5, characterized in that the plunger ( 203 ) in the section in which it passes through the piston seat ( 105 ), relative to the opening of the piston seat ( 105 ) is designed so that the fluid can flow in the open valve state in such an amount that nachzuschaltende consumers, such as injectors or a high-pressure fuel pump, are optimally supplied or slightly oversupplied. Electromagnetic control valve according to claim 5 or 6, characterized in that the plunger ( 203 ) in the section in which it passes through the piston seat ( 105 ) passes through, is designed so that it assumes an additional control function of the fluid flow. Injection system for an internal combustion engine, at least - with a prefeed pump ( 3 ) for conveying fuel from a fuel tank ( 2 ), - with one of the prefeed pump ( 3 ) downstream downstream high-pressure pump ( 4 ) for generating the injection pressure required for injection of the fuel into a combustion chamber of the internal combustion engine, - with a volume flow control valve ( 1 ), consisting of valve unit ( 10 ) and actuator ( 20 ) for controlling the high-pressure pump ( 4 ) supplied fuel flow between the feed pump ( 3 ) and the high pressure pump ( 4 ), wherein the valve unit ( 10 ) at least one valve housing ( 101 ), an inlet connection ( 102 ), a consumer connection ( 103 ) and a piston valve ( 104 ), which opposite the valve housing ( 101 ) is displaceable, and the actuator ( 20 ) at least one electromagnetic coil ( 201 ), a sliding anchor ( 202 ) and an axially arranged plunger ( 203 ), wherein the displaceable armature ( 202 ) over the axially arranged plunger ( 203 ) with the piston valve ( 104 ) is in operative connection, characterized in that - a seat valve ( 100 ) with a piston seat ( 105 ) between inlet connection ( 102 ) and consumer connection ( 103 ) is arranged and on the piston valve ( 104 ) on its the piston seat ( 105 ) facing a closing element ( 106 ), and - that the piston valve ( 104 ) on the inlet side ( 110 ) is arranged. Injection system for an internal combustion engine according to claim 8, characterized in that the seat valve ( 100 ) the maximum in the high pressure pump ( 4 ) limited available fuel flow. Injection system for an internal combustion engine according to claim 8 or 9, characterized in that the high pressure pump ( 4 ) downstream of a high-pressure valve ( 5 ) is arranged for pressure control without external control. Injection system for an internal combustion engine according to one of claims 8 to 10, characterized gekenn records that the flow control valve ( 1 ), consisting of valve unit ( 10 ) and actuator ( 20 ) according to one of claims 2 to 7 is formed.