Injector for injecting fuel

Abstract

The present invention relates to an injector for injecting fuel, comprising an injector housing for receiving at least one injector component, and an electromagnet for activating a valve for opening and closing the injector, wherein the electromagnet comprises a coil winding and a magnetic body, wherein the injector housing is formed in one piece with the magnetic body.

Claims

1. An injector for injecting fuel, comprising: an injector outer housing for receiving at least one injector component, the injector outer housing comprising a first injector housing portion and a second injector housing portion; and an electromagnet for activating a valve for opening and closing the injector, the electromagnet comprising a coil winding and a magnetic body having a magnetic inner pole inside the coil winding and a magnetic outer pole outside the coil winding, the first injector housing portion formed in one piece with the magnetic inner pole and comprising a conduit for supplying fuel.

2. The injector according to claim 1, wherein the coil winding is wound around an outer circumferential surface of the injector outer housing.

3. The injector according to claim 1, wherein the injector outer housing comprises a Cr—Mo-alloyed heat-treated steel.

4. The injector according to claim 1, wherein the injector outer housing comprises a second injector housing section, and both injector housing sections are joined in one piece to the magnetic body.

5. The injector according to claim 4, wherein the coil winding of the electromagnet is wound around an outer circumferential surface of the first injector housing portion.

6. The injector according to claim 4, further comprising a valve for exerting a variable pressure on an injector needle, wherein the second injector housing section adjoins the valve.

7. The injector according to claim 4, wherein the second injector housing section is joined in one piece to a part of the magnetic body provided outside the coil winding.

8. The injector according to claim 1, further comprising an anchor element for optional closing of a valve opening, wherein the anchor element is movable by the electromagnet.

9. The injector according to claim 8, wherein the anchor element is moved in an energized state of the electromagnet into a position in which the anchor element forms a magnetic circuit together with the magnetic inner pole and the magnetic outer pole of the magnetic body.

10. The injector according to claim 9, wherein the anchor element in this position contacts both the magnetic inner pole and the magnetic outer pole.

11. The injector according to claim 1, wherein the injector outer housing has a duct for the flowing of fuel from one or more bores distributed on the circumference.

12. An internal combustion engine with the injector according to claim 1.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Other features, details and advantages of the present invention are evident with reference to the following description of the figures. In these

(2) FIG. 1 shows a partial cross section of a conventional injector,

(3) FIG. 2 shows an extract of FIG. 1 in an enlarged depiction to explain the mode of operation of an injector,

(4) FIG. 3 shows a cross section of an injector according to the invention, and

(5) FIG. 4 shows an extract from FIG. 3 in an enlarged depiction to explain the different features compared with the prior art.

DETAILED DESCRIPTION

(6) FIG. 1 shows a partial sectional view of an injector from the prior art. The injector 1 is recognized, which has a housing 2 in which a plurality of injector components is arranged. Substantial for the function of the injector 1 here are the injector needle 5, the valve 4, the anchor element 6 and the electromagnet 3, which has a coil winding 31, an inner magnetic pole 32 and an outer magnetic pole 33. Moreover, there is provided in the inner magnetic pole 32 a recess for arranging the spring 8, which presses the anchor element 6 in the direction of the valve 4 in order to close the outlet throttle of the valve 4 in a fluid-tight manner in a de-energized state of the electromagnet.

(7) If the electromagnet 3 is activated, this pulls the anchor element 6 away from the valve 4 by means of magnetic force, so that fuel under high pressure can flow out of a control chamber that can be closed by the valve 4. Since the pressure in the control chamber that acts on the injector needle 5 is reduced by this, the latter can slide out of a closing position and permits the discharge of fuel from the injector 1. If the electromagnet 3 is put into a de-energized state, on the other hand, the magnetic force acting on the anchor element 6 decreases, so that the spring element 8 presses the anchor element 6 onto the outlet opening of the valve 4 and seals off the control chamber. The pressure acting on the injector needle 5 rises due to this, due to which this is pressed back into its closing position. A flow of fuel out of the outlet opening of the injector 1 accordingly no longer takes place.

(8) FIG. 2 shows an enlarged depiction in the lower area of the anchor element 6 in a closed state of the valve 4. The drain throttle 41 is recognized, which constitutes an outlet for fuel stored under high pressure in a control chamber 44. If the anchor element 6 is not on the sealing seat 45 of the valve 4, the fuel taken up under high pressure from the control chamber 44 can flow out via a passage space 42 into a low-pressure area. The valve 4 can also be provided here with a movable valve insert 43, by means of which the force acting on the injector needle 5 can be dissipated or built up particularly quickly.

(9) FIG. 3 shows a cross section along the longitudinal direction of an injector according to the invention. A duct 7 for supplying fuel is recognized, wherein this is arranged in a first housing section 21 of the injector 1. At the same time, the injector housing 2 also constitutes a magnetic body of the electromagnet 3. In the present figure, the injector housing 2 is divided into a first injector housing section 21 and a second injector housing section 22. The first injector housing section 21 is also an outer housing of the injector 1. Furthermore, the first injector housing section 21 is simultaneously a magnetic inner pole of the electromagnet 3. The second injector housing section 22 constitutes a magnetic outer pole of the electromagnet 3. The magnetic inner pole is separated from the magnetic outer pole by a coil winding 30. The first injector housing section 21 and the second injector housing section 22 are further characterized in that they each have a duct for carrying fuel in their bodies.

(10) FIG. 4 shows an enlarged section from FIG. 3, which shows the area around the electromagnet 3. The coil winding 31 is recognized, which is wound around an outer circumferential section of the first injector housing section 21 and thus constitutes the magnetic inner pole of the electromagnet 3 at the same time. Outside around the coil winding 31 there is further provided a magnetic outer pole 33, which simultaneously also constitutes a second injector housing section 22.

(11) A duct 7 for guiding fuel or another fluid runs here through the first injector housing section 21 and through the second injector housing section 22 also.

(12) In the state depicted in FIG. 4, the coil winding 31 is shown in an energized state, as the anchor element 6 is lifted from its closing position from the outlet throttle of the valve. To bring the anchor element 6 into such a position, it is necessary to overcome the closing force exerted by means of the spring 8, which is achieved by the electromagnet 3. In the configuration depicted a magnetic flux or a magnetic circuit is advantageously formed, which runs from the magnetic inner pole 32 via the anchor element 6 to the magnetic outer pole 33. A magnetic flux is accordingly created, therefore, via the injector housing 2 and the anchor element 6 (also: plunger).

(13) With an injector 1 formed in this way, the manufacturing costs for the solenoid valve can be reduced by approx. 85%. What is also advantageous about this is the lower number of components that can be achieved due to the now no longer separately required magnetic components.