# US 2014/0190451 A1 · Fuel injector for internal combustion engines

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- Number: US 2014/0190451 A1
- Document ID: US20140190451A1
- Status: Published application
- Kind: A1
- Application number: 14/124,764
- Filed: 2012-04-25
- Published: 2014-07-10
- Earliest claimed: 2011-06-09
- Assignees: Robert Bosch GmbH
- Inventors: Marco Vorbach
- Web page: https://patentgrep.com/patent/US20140190451A1

## CPC

- F02M 69/04: Injectors peculiar thereto
- F02M 61/06: the valves being furnished at seated ends with pintle or plug shaped extensions
- F02M 61/1806: {characterised by the arrangement of discharge orifices, e.g. orientation or size}
- F02M 61/188: {Spherical or partly spherical shaped valve member ends}
- F02M 61/1886: {Details of valve seats not covered by groups F02M61/1866 - F02M61/188}
- F02M 61/1893: {Details of valve member ends not covered by groups F02M61/1866 - F02M61/188}
- F02M 2200/06: Fuel-injection apparatus having means for preventing coking, e.g. of fuel injector discharge orifices or valve needles
- F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF

## Abstract

A fuel injector for internal combustion engines is provided, which has a valve seat member, bordering a valve chamber, having a valve seat and spray orifices and a central blind-end bore as well as a valve member that is able to be driven to cause a lift motion having a closing head, which, together with a valve seat, forms a sealing seat lying upstream of the spray orifices. In order to prevent an underpressure developing in the blind-end bore in the closing phase of the sealing seat, and a partial return flow of the fuel connected with it, the closing head of the valve member is provided, at its end face facing towards the valve seat member, with a plunger sticking out from closing head, which has a shape adjusted to the contour of the blind-end bore, and dips into the blind-end bore when the sealing seat is closed.

## Claims

### Claim at position 1

1-8. (canceled)

### Claim 9

A fuel injector for an internal combustion engine, comprising:
a valve seat member that includes:
a valve chamber,
an inner body wall bordering the valve chamber,
a valve seat developed on the inner body wall,
a plurality of spray orifices having orifice entry openings lying in the inner body wall, and
a blind-end bore worked into a region of the inner body wall that is enclosed by the orifice entry openings;
a valve member that is able to be driven to perform a lifting motion, the valve member including a closing head which, with the valve seat, forms a sealing seat lying upstream of the orifice entry openings of the spray orifices; and
a plunger sticking out from the closing head at an end face of the closing head facing towards the valve seat member, wherein:
the plunger has a shape adjusted to a contour of the blind-end bore, and
the plunger is situated in such a way that the plunger dips into the blind-end bore upon a closing of the sealing seat.

### Claim 10 (depends on 9)

The fuel injector as recited in claim 9, wherein the blind-end bore and the plunger are adjusted to each other so that the plunger lies in the blind-end bore in a form-locking manner when the sealing seat is closed.

### Claim 11 (depends on 9)

The fuel injector as recited in claim 9, wherein:
the blind-end bore is developed as a hollow,
the plunger is developed as a protuberance, and
the blind-end bore and the plunger are one of bell-shaped and hat-shaped.

### Claim 12 (depends on 11)

The fuel injector as recited in claim 11, wherein:
the hollow has an elevation sticking out centrically from a hollow base, and
the protuberance has a centrical depression having a contour that is adjusted to a shape of the elevation.

### Claim 13 (depends on 9)

The fuel injector as recited in claim 9, wherein the blind-end bore and the plunger have a frustoconical shape.

### Claim 14 (depends on 9)

The fuel injector as recited in claim 9, wherein the plunger is connected in an attached form in one piece to the closing head.

### Claim 15 (depends on 9)

The fuel injector as recited in claim 9, wherein:
all the orifice entry openings of the spray orifices are situated on a circle that is concentric with an axis of the valve seat member, at a distance from one another, and
an axis of the blind-end bore is in alignment with the axis of the valve seat member.

### Claim 16 (depends on 15)

The fuel injector as recited in claim 15, wherein the orifice entry openings have the same distance from one another in a circumferential direction

### Claim 17 (depends on 9)

The fuel injector as recited in claim 9, wherein:
the spray orifices have orifice sections that are stepped in cross section, and
the orifice sections have a cross section that increases from the orifice entry openings to orifice exit openings.