JP3223072B2 - Plunger assembly - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates in general relates to a plunger assembly of the fuel injector, in particular, plastics which comprises a high timing plunger (resistant against scuffing) scuffing resistance made from a ceramic material
Pertains to an assembly .

[0002]

BACKGROUND OF THE INVENTION Fuel injector timing plungers are required to operate under extremely adverse environmental conditions in a fuel injector assembly.
A high mechanical load (high load) is imposed on the timing plunger both in the axial direction and in the vertical direction.
The timing plunger must be reciprocated within the bore of the injector body, which often becomes distorted and cannot maintain its original diameter clearance, so that it is pressed against the bore wall during operation of the injector, resulting in scuffing. Occurs. Further, poor quality and contaminated fuel (fuel) contributes to creating a disadvantageous operating environment for the timing plunger.

The materials of timing plungers have changed over the years to produce timing plungers that are required to be scuff and abrasion resistant under the adverse conditions of the fuel injector environment. However, the third body debris (dust) interferes with the effective injector function. The third body debris includes particles that are not intended to be present in the injector and that are harder than the plunger or injector body. Such particles become buried in the surface of the timing plunger, and eventually the plunger and the injector body are forcibly pushed together, so that the plunger cannot reciprocate in the bore of the injector body and friction is generated. We come to weld. The reduced lubricity of the fuel, which can be caused by water contamination of the fuel, is also a factor contributing to the friction welding of the timing plunger and injector body. When this occurs, the operation of the injector is, of course, hindered.

The prior art has proposed the use of wear and corrosion resistant materials to form various structures and components of internal combustion engines. See, for example, Gill U.S. Pat.
U.S. Pat. No. 4,8,94,894 and Benz.
No. 48,040 relates to a ceramic-edged pivot rod, and to U.S. Pat. No. 4,806,040 to Gil et al.
Relates to ceramic ball and socket joints. U.S. Pat. No. 4,266,729 to Kulke et al.
Disclosed is to manufacture the injector valve needle tip and / or disc from a corrosion resistant material such as high quality steel, ceramic, or technical glass. However, the inventor of any of these patents has addressed certain issues such as scuffing and sticking of the fuel injector timing plunger encountered by the fuel injectors utilized, particularly those used in diesel engines. There is nothing.

[0005] Several types of fuels increasingly used in diesel engines, particularly low lubrication alternative fuels, and fuels that can become water contaminated, have a high scuff resistance to maintain effective engine operation. Requires a fuel injector timing plunger. The prior art is sufficiently scuff and abrasion resistant to operate effectively, especially when exposed to a third body debris and under adverse operating conditions such as low lubricity and contaminated fuel. Failure to provide a fuel injector timing assembly that includes a timing plunger.
Such a fuel injector timing plunger is required.

[0006]

Accordingly, it is a primary object of the present invention to overcome the deficiencies of the prior art and to provide a scuff-resistant timing plunger for a unitary fuel injector for an internal combustion engine powered by a diesel fuel. Including a fuel injector plunger assembly.

Another object of the present invention is to provide a fuel injector including a timing plunger for a diesel engine which can operate effectively when a high load is applied to the timing plunger in an axial direction and a direction oblique to the axial direction. It is to provide a plunger assembly.

It is a further object of the present invention to provide a diesel engine fuel injector timing plunger that is wear and scuff resistant so as not to stick during operation of the fuel injector, while maintaining optimal diameter clearance. .

It is another object of the present invention to provide a reliable fuel injector timing assembly for an internal combustion engine that includes a wear and scuff resistant timing plunger arranged to reciprocate within an injector body. To provide.

[0010]

SUMMARY OF THE INVENTION The object of the present invention is to provide abrasion resistance and scuff resistance so that it can freely reciprocate without sticking under a disadvantageous condition in a unit type fuel injector body. At the same time, maintain sufficient diameter clearance in the injector body,
This is achieved by providing a fuel injector timing assembly that includes a unitary fuel injector timing plunger for a diesel engine operably disposed within an injector body. The injector timing plunger is highly correlated with the coefficient of thermal expansion of the fuel injector body to provide optimal operating clearance between the plunger and the injector body during engine operation, while preventing fuel leakage around the timing plunger. It is manufactured from a ceramic material having a certain coefficient of thermal expansion.

A first aspect of the present invention is a plunger assembly for a high performance internal combustion engine unit type fuel injector operatively connected to a drive train for injecting fuel into an engine cylinder, the fuel injector being connected to the drive train. A metal fuel injector body provided between the linked link and the nozzle end of the fuel injector, wherein the plunger assembly is disposed through the fuel injector nozzle end through the fuel injector nozzle end. In order to inject a controlled amount of fuel into the engine cylinder at a desired interval, an axial direction from the drive train and within an axial bore of the injector body.
Make a reciprocating motion with a load applied in a direction perpendicular to that direction.
A scuff and wear resistant timing plunger having a predetermined diameter clearance with respect to the axial bore , wherein the timing plunger includes a bore in the axial bore.
Has a predetermined plunger diameter slightly smaller than the diameter
And, 6 × 10 ^-6 / ° larger than C, and -40 ° C~1
A coefficient of thermal expansion substantially equal to the coefficient of thermal expansion of the metal forming the fuel injector body in a temperature range of 40 ° C . ;
g / mm ² hardness and lubrication inside the axial bore
Low reactivity and low adhesion to the fuel
Manufactured in wear-resistant ceramic material having an affinity, the off relative to the axial bore in the fuel injection event
The timing plan without excessive leakage of fuel
The optimum range for smooth and reliable lubrication .
And sized to maintain said predetermined diameter clearance 001930～0.003251Mm, outside of the plunger
Optimal lubrication between the peripheral surface and the inner peripheral surface of the axial bore
And that the fuel leaks excessively
The outer peripheral surface of the plunger and the axial bore
The predetermined diameter clearance with the inner peripheral surface of the is maintained,
A plunger assembly characterized by the above-mentioned.

[0012]

[0013] The third aspect of the present invention is directed to the first aspect.
Or in the second aspect, the plunger assembly includes:
A homogeneous and chemically inert material selected from the group consisting of zirconia , alumina-zirconia , and alumina ceramics.
Manufactured from an active hard ceramic material . The present invention
A fourth aspect of the present invention is the embodiment of the third aspect, wherein
The lamic material is a zirconia ceramic.

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

Other objects and advantages will become apparent from the following description, the appended claims, and the drawings.

[0021]

DETAILED DESCRIPTION OF THE INVENTION Fuel injector timing plunger scuffing and sticking is one of the causes of high injector RPH (Repairs Per Hundred). High warranty costs can result from replacing a damaged and inoperable timing plunger. Fuel injector body of the present invention /
The timing plunger assembly provides a reliable, wear-resistant timing plunger that does not stick and scuff even when exposed to extremely adverse engine operating conditions. Thus, the present invention effectively reduces both the injector RPH and the warranty cost caused by a damaged and inoperable timing plunger.

Referring to the drawings, FIG. 1 shows an open nozzle unitary fuel injector 10 having a timing assembly of the type including a timing plunger 12.
Is shown in a sectional view. This type of fuel injector includes a body 14 and an injector nozzle 16. Injector nozzle 16 and body 14 are axially aligned and held together by retainer 18. The axial bore 20 extends through the entire length of the body 14. A plurality of injection orifices 22 spaced at the nozzle 16 are provided at the end of the injector cup to optimize fuel injection.

The injector 10 has a rocker lever 26
The timing plunger 12 reciprocates axially within the injector with a link 24 engaged by one end of the plunger. The other end of the rocker lever 26 is drivingly connected to a camshaft 28 via a push tube 30. Rocker lever 26 generally applies both axial and perpendicular loads to timing plunger 12 during operation of the engine. The arrow (A) indicates the axial load applied to the timing plunger 12 by the rocker lever 26. The arrow (B) indicates the rocker lever 26.
Indicates the vertical or lateral load applied to the timing plunger 12 by. Timing plunger 1
The axial load applied to the timing plunger 12 by the rocker lever 26 when the cylinder 2 reciprocates in the injector body 14 is approximately 1,088.62 kg (2
400 pounds). In addition to such axial and vertical loads, when the timing plunger moves toward the injector nozzle 16, it is about 168,921.6 kPa (24,500 ps).
A high pressure, which extends to i), is generated by the downward stroke of the timing plunger. This results in the timing plunger 12 moving axially upwards, ie, away from the nozzle 16 and toward the rocker lever 26, as shown by arrow (C), about 168,921.6 kPa.
(24,500 psi).

Ceramic timing plunger 12
Is about 0.0019 for the injector body bore 20
30 mm to 0.003251 mm (0.000076 to 0.
000128 inches). The diameter clearance can be smaller than that of known plunger designs due to the difference in thermal expansion between the currently available stainless steel plunger and the ceramic timing plunger 12. The aforementioned load on the timing plunger and the clamping load on the injector body 14 often distort the axial bore to reduce the diametral clearance. The rocker lever, which has created a lateral load (arrow B), then pushes the timing plunger 12 against the wall of the body bore 20. Under such circumstances, plunger scuffing and wear occur. The presence of a third body debris in the injector body
Under such loads, the problem of the plunger is increased.

The harshness of the operating environment of the timing plunger is further increased by low sulfur, low lubrication fuels and water contaminated fuels. Until the present invention, there has been obtained a fuel injector timing plunger that is scuff and wear resistant and that can function without sticking or damage under adverse operating conditions encountered in the operating environment of a fuel injector. I couldn't.

The present invention provides a fuel injector timing plunger assembly for an internal combustion engine unit fuel injector that includes a timing plunger having substantially higher resistance to scuffing and sticking than currently used timing plungers. Making the injector timing plunger from a hard, wear-resistant ceramic material avoids the scuffing and sticking problems that plague steel and other metal plungers, and further reduces engine operating time than currently available timing plungers. Has been found to withstand the axial and vertical loads applied to it. Ceramic timing plungers offer many advantages. The type of ceramic material suitable for use as a timing plunger is much harder than the material currently used for either the timing plunger or the injector body. Furthermore, ceramic materials have low reactivity and low affinity for adhesion with petroleum that lubricates metal interfaces. However,
An optimal surface finish must be such that the sliding wear performance is best.

[0027] Timing plungers made from ceramics having high thermal expansion, including zirconia , alumina-zirconia , and alumina, have been shown to exhibit substantially better scuff resistance than plungers made from metal. Other ceramics, the most famous of which are silicon nitride, also exhibit excellent scuff resistance, but only ceramics with high thermal expansion are suitable for use in forming unitary fuel injector timing plungers. It has been found. Optimum leakage of fuel around the plunger during engine operation is important. Ceramics with low thermal expansion allow excessive leakage, so ceramics with high thermal expansion can be maintained within parameters that allow fuel leakage. The preferred ceramic material used to form the fuel injector timing plunger is 6 ×
Having a coefficient of thermal expansion greater than 10 ⁻⁶ / ° C.
It has a hardness of more than 00 kg / mm ² .
The coefficient of thermal expansion of the ceramic selected for the timing plunger should be as close as possible to that of the metal forming the injector body.

FIG. 2 compares the diameter of the injector body bore 20 (FIG. 1) to the diameter of the currently used timing plunger and the diameter of two ceramic plungers with different diameter clearances. Curve A shows the injector body bore diameter over the temperature range tested. Curve B shows the change in plunger diameter when the timing plunger 12 is made of stainless steel (which is the material currently used).
The diameter clearance between the stainless steel timing plunger and the injector bore in the tested assembly was 5.0 μm. Curves C and D show the change in timing plunger diameter for two ceramic timing plungers with different clearances. The diameter clearance between the timing plunger and the bore of the assembly shown by curve C was 2.5 μm, while the diameter clearance between the timing plunger and the bore of the assembly shown by curve D was 5.0 μm. FIG. 2 shows that a ceramic timing plunger according to the present invention can have a smaller diameter clearance in the injector bore than currently used stainless steel plungers, and the timing plunger is loaded during engine operation. It clearly shows that it can work effectively in some cases.

As described above, the unitary fuel injector timing plunger having the characteristics of high coefficient of thermal expansion and high hardness has survived very harsh bench and engine tests that have broken the standard steel timing plunger. Injector RPH and warranty costs have been reduced by using ceramic timing plungers in the timing assembly of the unitary fuel injector.

The timing plunger of the present invention will find major applicability as an integral component of the injector timing plunger assembly of a unitary fuel injector in an internal combustion engine, especially a heavy duty (high load) diesel engine.

[0031]

The present invention provides a fuel injector plunger assembly that includes a scuff-resistant timing plunger for a unitary fuel injector powered by a diesel fuel for an internal combustion engine.

Further, according to the present invention, there is provided a fuel injector plunger assembly including a timing plunger for a diesel engine capable of effectively operating when a high load is applied to the timing plunger in an axial direction and a direction oblique to the axial direction. Provided.

Further, the present invention provides a diesel engine fuel injector timing plunger that is wear and scuff resistant so as not to stick during operation of the fuel injector, while maintaining optimal diameter clearance.

Further, the present invention provides a reliable fuel injector timing assembly for an internal combustion engine that includes a wear and scuff resistant timing plunger arranged to reciprocate within the injector body.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a fuel injector assembly in a diesel engine having a scuff-resistant, non-sticking timing plunger of the present invention.

FIG. 2 graphically illustrates the size of the injector body bore and timing plunger of the present invention of different materials at different temperatures.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Open nozzle unit type fuel injector 12 Timing plunger 14 Body 16 Nozzle 18 Retainer 20 Axial bore 22 Orifice

Continuation of front page (72) Inventor Jay. Victor Pale United States of America 46143 Greenwood North Graham Road 487 (72) Inventor David M. Rix United States of America 47201 Columbus Lawton Avenue 1492 (72) Inventor Joseph Sea. Benz United States of America 47203 Columbus Auriol Drive 3530 (72) Inventor Thomas M. Yonushonis United States 47201 Columbus Mallard Point 4412 (72) Inventor Malcolm G. Naylor USA 47247 Jonesville P. O. Box 93 (No address) (72) Inventor Kazuhiro Shinozawa 2-4 Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside Keihin Plant, Toshiba Corporation (72) John T. Inventor. Carol the Third, Columbus, Kaya Square, Indiana, United States 730 Panel Referee Chief Yoshio Nishikawa Referee Yoshiaki Tamura Referee Masahiro Kurita (56) References JP-A-6-137231 (JP, A) Jpn. , U) Hisao Sakano, Yukiyasu Asano, "Automotive Engineering Series Automotive Ceramics", Sankaido Co., Ltd., April 15, 1987, P56-57 (58) Fields investigated (Int. Cl. ⁷ , DB name) ) F02M 57/02

Claims (3)

(57) [Claims] A plunger assembly for a high performance internal combustion engine unit fuel injector operatively connected to a drive train for injecting fuel into an engine cylinder, the link being connected to the drive train and the fuel injector being connected to the drive train. A plunger assembly operatively disposed axially within a metallic fuel injector body provided between the fuel injector body and a nozzle end, wherein the plunger assembly is provided at a desired interval to the engine cylinder via the fuel injector nozzle end. , to inject controlled fuel amount, before within the axial bore of the injector body
In the axial direction from the drive train and in the direction perpendicular to it.
The axial bore, which reciprocates under load, is
A scuff-resistant and wear-resistant timing plunger having a predetermined diameter clearance , wherein the timing plunger has a bore diameter of the axial bore.
A predetermined plunger diameter slightly smaller than the diameter,
Greater than 6 × 10 ⁻⁶ / ° C. and −40 ° C. to 140
A coefficient of thermal expansion substantially equal to the coefficient of thermal expansion of the metal forming the fuel injector body in the temperature range of 800 ° C .;
Hardness greater than ² mm2 and lubricating inside the axial bore
Low reactivity and low affinity for adhesion to the fuel
The fuel bore is made of a wear-resistant ceramic material having an elasticity , and the fuel is injected into the axial bore during the fuel injection operation.
Timing plunger without excessive leakage
Is the optimal range for smooth and reliable lubrication.
And sized to maintain said predetermined diameter clearance 1930～0.003251Mm, the outer peripheral surface of the plunger and the inner peripheral surface of the axial bore
Maintain optimal lubrication between the
Outer periphery of the plunger to prevent excessive leakage
A predetermined diameter clearer between a surface and an inner peripheral surface of the axial bore;
A plunger assembly, wherein the plunger is maintained . Wherein said timing plunger, zirconia, alumina - zirconia, and a homogeneous selected from the group consisting of ceramics of alumina is produced from chemically inert hard ceramic material, according to claim 1 plunger assembly. 3. The plunger assembly according to claim 1 , wherein said timing plunger is a zirconia ceramic.