Granted Patent B2

US 10,408,176 · App. 15/747,779 · Granted Sep 10, 2019

Abstract

Claims (23)

1. A fuel injector comprising:

a control valve which controls fuel pressure in a control chamber, the control valve comprising:

a valve seat;

a valve member having a valve face for cooperating with the valve seat to control fuel pressure in the control chamber;

a return line for returning fuel from the control chamber;

an armature connected to the valve member, the armature being disposed in an armature chamber;

an actuator for actuating the armature; and

a deflector disposed in the armature chamber which forms a first sub-chamber and a second sub-chamber, the first sub-chamber and the second sub-chamber being in fluid communication with each other via at least one first aperture;

wherein, in use, a pressure differential is established between the first sub-chamber and the second sub-chamber when the valve face lifts from the valve seat promoting the flow of fuel from the second sub-chamber into the first sub-chamber through the at least one first aperture,

wherein the at least one first aperture is configured to establish communication between radially inner ends of the first sub-chamber and the second sub-chamber,

wherein the at least one first aperture is disposed proximal to the valve seat,

wherein the at least one first aperture has a radial width in the range 0.0325 mm to 0.2825 mm inclusive.

2. A fuel injector as claimed in claim 1 , wherein the at least one first aperture is an annular aperture extending circumferentially around the valve member.

3. A fuel injector as claimed in claim 1 , further comprising at least one second aperture which facilitates circulation between the first sub-chamber and the second sub-chamber.

4. A fuel injector as claimed in claim 3 , wherein the valve seat and the at least one second aperture are formed at opposing ends of the armature chamber.

5. A fuel injector as claimed in claim 4 , wherein the at least one second aperture has a longitudinal dimension of at least 0.05 mm.

6. A fuel injector as claimed claim 1 , wherein the control valve opens into the first sub-chamber; and the second sub-chamber is formed between the deflector and the armature.

7. A fuel injector as claimed in claim 1 , wherein the valve member comprises a longitudinal bore which is open at a first end and a second end.

8. A fuel injector as claimed in claim 7 , wherein the first end of the longitudinal bore opens into a collection chamber; the collection chamber either being closed or connected to the return line.

9. A fuel injector as claimed in claim 7 , wherein the second end of the longitudinal bore opens into a chamber above the armature and at least one third aperture is maintained between the actuator and the armature when the control valve is open.

10. A fuel injector as claimed in claim 9 , wherein the at least one third aperture comprises a clearance between an upper face of the armature and an opposing face of the actuator.

11. A fuel injector as claimed in claim 10 , wherein the clearance between the upper face of the armature and the opposing face of the actuator is between 0.01 mm and 0.06 mm.

12. A fuel injector as claimed in claim 1 , wherein an underside of the deflector is spaced apart from a bottom of the armature chamber by a longitudinal offset in the range 0.3 mm to 0.4 mm.

Assignments (6)