Fuel injection valve and method of manufacturing the same

• US 5,996,910 A
• Filed: 11/04/1997
• Issued: 12/07/1999
• Est. Priority Date: 11/13/1996
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Suzuki, Haruo, Funahashi, Masaki, Sugiyama, Satoshi, Iwanari, Eiji, Tanimura, Yoshihiro, Takeda, Hideto
• Primary Examiner(s): Kashnikow, Andres
• Assistant Examiner(s): Ganey, Steven J.
• Application Number:
  US08/964,220
• Time in Patent Office: 763 Days
• Field of Search: 239/585.1-585.5, 239/600, 239/DIG. 19, 251/129.15, 251/129.16, 251/129.21, 29/888.4, 29/890.143
• US Class Current: 239/585.1
• CPC Class Codes: F02M 2200/505 Adjusting spring tension by sliding spring seats
• CPC Class Codes: F02M 51/0614 characterised by arrangement of electromagnets or fixed armature
• CPC Class Codes: F02M 51/0675 the valve body having cylindrical guiding or metering portions, e.g. with fuel passages
• CPC Class Codes: F02M 51/0678 all portions having fuel passages, e.g. flats, grooves, diameter reductions
• CPC Class Codes: F02M 61/168 Assembling; Disassembling; Manufacturing; Adjusting
• CPC Class Codes: Y10S 239/19 Nozzle materials
• CPC Class Codes: Y10T 29/49298 Poppet or I.C. engine valve or valve seat making
• CPC Class Codes: Y10T 29/49433 Sprayer

Abstract

A fuel injection valve has a single pipe member made of composite magnetic material which can be processed to form ferro-magnetic structures and non-magnetic structures. A magnetic fuel connector, a magnetic valve body, a nonmagnetic intermediate pipe are formed in the single pipe member. An electromagnetic solenoid is disposed around the intermediate pipe, and a needle valve is disposed in the valve body. A magnetic stationary core is disposed inside the fuel connector, and a magnetic movable core is disposed inside the valve body in a magnetic circuit composed of the solenoid, the fuel connector, the stationary core and the valve body.

Claims

1. A fuel injection valve having a magnetic fuel connector, and a magnetic valve body, a nonmagnetic intermediate pipe connected between said fuel connector and said valve body, an electromagnetic solenoid disposed around said intermediate pipe, a needle valve disposed in said valve body, a magnetic stationary core disposed inside said fuel connector and a magnetic movable core disposed inside said valve body in a magnetic circuit composed of said solenoid, said fuel connector, said stationary core and said valve body, wherein

said fuel connector, said intermediate pipe and said valve body are formed integrally in a unitary member made of composite magnetic material;

said fuel connector and said valve body are ferro-magnetized to form a magnetic circuit between said stationary core and said movable core, and

said intermediate pipe is non-magnetized to magnetically insulate said fuel connector from said valve body, wherein;

said stationary core comprises a member made of magnetic composite material having a ferro-magnetized structure and a non-magnetized structure disposed to divide said ferro-magnetized structure to provide a solid gap.

2. A fuel injection valve comprising:

a unitary pipe made of a composite magnetic material including a ferromagnetic fuel connector portion disposed at one end thereof, a ferromagnetic valve body portion disposed at the other end thereof and non-magnetic intermediate pipe portion disposed between said fuel connector portion and said valve body portion;

an electromagnetic solenoid disposed outside said unitary pipe around said intermediate pipe portion;

a needle valve disposed inside said unitary pipe at said valve body portion;

a magnetic stationary core disposed inside said unitary pipe at a portion of said intermediate pipe portion and also extending along al least a portion of said fuel connector portion to provide a surface receiving magnetic flux from said fuel connection portion; and

a magnetic movable core disposed inside said unitary pipe to face an axial end of said stationary core through a magnetic gap and fixed to said needle valve to form a magnetic circuit for said solenoid together with said fuel connector portion, said stationary core and said valve body, and to be slidable on the inner periphery of said valve body portion.

3. A fuel injection valve as in claim 2 wherein said stationary core is press-fitted to said fuel connector.

4. A fuel injection valve as in claim 3 wherein:

said stationary core comprises a cylindrical member having a longitudinal slit.

5. A fuel injection valve as in claim 2 wherein:

said valve body comprises an integral valve seat having ferro-magnetized structure.

6. A fuel injection valve as in claim 2 wherein:

said fuel connector has an inner diameter which is equal to or larger than an inner diameter of said intermediate pipe.

7. A fuel injection valve as in claim 2 further comprising:

a pair of O-rings for sealing spaces formed when said valve is installed into an engine, and wherein said solenoid is disposed between said O-rings.

8. A fuel injection valve as in claim 2 wherein said axial end of said stationary core and the surface of said movable core facing said axial end are chrome-plated to form a solid magnetic gap.

9. A fuel injection valve as in claim 2 wherein said axial end of said stationary core is disposed at about a middle of said intermediate pipe.

10. A fuel injection valve comprising:

a unitary pipe composed of a magnetic fuel connector portion at one end thereof, a magnetic valve body portion at the other end thereof, and a non-magnetic intermediate pipe portion between said fuel connector portion and said valve body portion;

an electromagnetic solenoid disposed outside said unitary pipe around said intermediate pipe;

a magnetic stationary core disposed inside said unitary pipe to extend axially to provide a surface sufficient to receive magnetic flux from said fuel connector portion;

a magnetic movable core disposed to be magnetically spaced apart from said stationary core inside said unitary pipe to form a magnetic circuit for said solenoid together with said fuel connector portion, said stationary core and said valve body portion,

wherein said unitary pipe is made of material that can be changed from magnetic material to non-magnetic material.

11. A fuel injection valve comprising:

a generally straight and smooth unitary pipe composed of a martensitic fuel connector portion at one end thereof, a martensitic valve body portion at the other end thereof, and an austenitic intermediate pipe portion between said fuel connector portion and said valve body portion;

an electromagnetic solenoid disposed outside said unitary pipe around said intermediate pipe;

a magnetic stationary core disposed inside said unitary pipe to extend axially to provide a surface sufficient to receive magnetic flux from said fuel connector portion;

a magnetic movable core disposed inside said unitary pipe to form a magnetic circuit for said solenoid together with said fuel connector portion, said stationary core and said valve body portion.

12. A fuel injection valve comprising:

a unitary pipe made of a composite material capable of being selectively made to have ferromagnetic properties or not to have ferromagnetic properties;

said pipe having an intermediate portion not having ferromagnetic properties located between first and second portions having ferromagnetic properties;

an electromagnetic solenoid disposed outside said unitary pipe at said intermediate portion and extending along at least part of said first and second portions;

a needle valve disposed inside said unitary pipe at said second portion;

a stationary ferro-magnetic core disposed inside said unitary pipe at said intermediate portion and extending along a part of said first portion to provide a surface receiving magnetic flux from said first portion; and

a movable ferromagnetic core disposed inside said unitary pipe to face an axial end of said stationary core through a magnetic gap and fixed to said needle valve to form a magnetic circuit for said solenoid together with said first portion, said second portion, and said stationary core while being slidable on an inner periphery of said second portion.