United States Court of Appeals for the Federal Circuit 

05-1407 

HONEYWELL INTERNATIONAL, INC. 

and HONEYWELL INTELLECTUAL PROPERTIES, INC., 

Plaintiffs-Appellants, 

v. 

ITT INDUSTRIES, INC. and ITT AUTOMOTIVE, INC., 

Defendants-Appellees, 

and 

TG NORTH AMERICA CORPORATION, 

TG FLUID SYSTEMS USA CORPORATION, and A. RAYMOND, INC., 

Defendants-Appellees. 

 Dan L. Bagatell, Perkins Coie Brown & Bain P.A., of Phoenix, Arizona, argued for 

plaintiffs-appellants. Of counsel on the brief were R. Terrance Rader and Glenn E. 

Forbis, Rader, Fishman & Grauer PLLC, of Bloomfield Hills, Michigan. Of counsel was 

Kristin L. Murphy, Rader, Fishman & Grauer PLLC. 

 Thomas N. Young, Young & Basile, P.C., of Troy, Michigan, argued for 

defendants-appellees, ITT Industries, Inc., et al. 

Stephen L. Sulzer, Connolly Bove Lodge & Hutz LLP, of Washington, DC, argued 

for defendants-appellees, TG North America Corporation, et al. With him on the brief 

was James P. Calve. 

Appealed from: United States District Court for the Eastern District of Michigan 

Senior Judge Avern Cohn 
United States Court of Appeals for the Federal Circuit 

05-1407 

HONEYWELL INTERNATIONAL, INC. 

and HONEYWELL INTELLECTUAL PROPERTIES, INC., 

 Plaintiffs-Appellants, 

v. 

ITT INDUSTRIALS, INC. and ITT AUTOMOTIVE, INC., 

Defendants-Appellees, 

and 

TG NORTH AMERICA CORPORATION, 

TG FLUID SYSTEMS USA CORPORATION, and A. RAYMOND, INC., 

 Defendants-Appellees. 

_____________________ 

DECIDED: June 22, 2006 

_____________________ 

Before MAYER, LOURIE, and DYK, Circuit Judges. 

LOURIE, Circuit Judge. 

Honeywell International, Inc. and Honeywell Intellectual Properties, Inc. 

(collectively “Honeywell”) appeal from the final decision of the United States District 

Court for the Eastern District of Michigan granting summary judgment of 

noninfringement of U.S. Patent 5,164,879 in favor of ITT Industrials, Inc., ITT 

Automotive, Inc., TG North America Corporation, TG Fluid Systems USA Corporation, 

and A. Raymond, Inc. (collectively “ITT/TG”). Honeywell Int’l, Inc. v. ITT Indus., Inc., 

Civ. No. 02-73948 (E.D. Mich. April 27, 2005). Because the district court correctly 
construed the claim limitation “fuel system component” and determined that the accused 

products do not meet that limitation, we affirm its grant of summary judgment of 

noninfringement. We further conclude that under our modified construction of the claim 

limitation “electrically conductive fibers,” the accused products do not meet that 

limitation either, thereby providing a separate ground for affirming the district court’s 

grant of summary judgment of noninfringement. 

BACKGROUND 

The ’879 patent, entitled “Electrostatically Dissipative Fuel System Component,” 

discloses a fuel filter that is specially made for use in motor vehicles that have electronic 

fuel injection (“EFI”) systems. Before motor vehicles began using EFI systems, the 

housing of a fuel filter was commonly made of metal or a polymer material. ’879 Patent, 

col.1 ll.10-12 (filed July 1, 1991). Once vehicles began using EFI systems, as the ’879 

patent’s written description recognizes, fuel filters with polymer housing began to break 

down and start leaking. Id., col.1 ll.17-20. It was discovered that the breakdowns were 

caused by the contact between the fuel, which flows at a high velocity in EFI systems, 

and the fuel filter’s polymer housing. The resultant friction strips electrons from the 

hydrocarbon fuel and traps them in the non-conductive polymer housing, which leads to 

an electrostatic charge buildup within the housing of the fuel filter. Id., col.1 ll.26-30. 

The charge continues to build up until it finally discharges by “arcing” onto the vehicle’s 

metal frame and becomes grounded. “Arcing” forms microscopic holes in the fuel filter’s 

housing. Id., col.2 l.59 to col.3 l.2. When enough microscopic holes are formed, the 

fuel begins to leak. Fuel filters with metal housing avoid the “arcing” phenomenon 

because they allow no charge buildup. The conductive nature of metal prevents the 

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electrons from being trapped inside the fuel filter and allows them to pass through to the 

vehicle’s frame. Fuel filters with housing made of polymer material, however, are more 

desirable than their metal housing counterparts because of their lower cost and weight. 

Id., col.1 ll.13-14. 

The patented invention addresses the “arcing” problem in fuel filters with polymer 

housing by providing an electrically conductive pathway between the fuel filter and the 

vehicle’s metal frame. Id., col.3 ll.41-43. The electrically conductive pathway prevents 

the electrostatic charge from building up within the housing of the fuel filter. Id., col.3 

ll.3-6. According to the written description, the electrically conductive pathway is 

created by incorporating small amounts of a “conductive filler material” into the polymer 

housing. Id., col.3 ll.47-51. The written description further discloses that stainless steel 

is an ideal “conductive filler material” because it has high conductivity, allowing it to be 

used in fibers with a high aspect ratio. Id., col.3 l.53 to col.4 l.13. The written 

description also notes that stainless steel fibers are ductile, which allows them to better 

maintain their integrity during melt-processing. Id. The benefits of stainless steel fibers 

are contrasted in the written description to electrically conductive carbon fibers, which 

are said to have less desirable characteristics, e.g., they must be used in fibers with 

smaller aspect ratios, are more rigid, and act as stress concentrators. Id., col.3 ll.56-60; 

col.4 ll.1-5. 

Turning to the prosecution history of the patent in suit, the ’879 patent issued 

from a divisional application of U.S. Patent Application 575,260, which issued as U.S. 

Patent 5,076,920 and was entitled “Electrostatically Dissipative Fuel Filter.” Also issuing 

from a divisional application of the ’260 application was U.S. Patent 5,164,084, also 

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entitled “Electrostatically Dissipative Fuel Filter.” The drawing and written description 

sections for the ’879, ’920, and ’084 patents appear to be identical. See Honeywell Int’l, 

Inc. v. ITT Indus., Inc., 330 F. Supp. 2d 865, 871 (E.D. Mich. 2004). The patent 

examiner for the ’260 application issued a restriction requirement in that application 

because it claimed three distinct inventions: (1) a method for preventing breakdown of 

a fuel filter, (2) the fuel filter itself, and (3) a moldable polymeric material. Id. Faced

with this restriction requirement, the patentee chose the first invention for immediate 

prosecution, a method for preventing breakdown of a fuel filter, and that became the 

claimed subject matter of what issued as the ’920 patent. The patentee filed divisional 

applications for the remaining inventions resulting in two other patents, the ’084 patent 

(for a fuel filter) and the ’879 patent (for a moldable polymeric material), the patent at 

issue in this case. 

The ’879 application, as initially filed, was entitled “Electrostatically Dissipative 

Fuel Filter” and contained one independent claim directed to a “moldable material for 

fuel system components.”1

 The patent examiner rejected the claim on the ground of, 

inter alia, indefiniteness under 35 U.S.C. § 112, ¶ 2. According to the examiner, it was 

“not clear what fuel system components [were] intended to be constructed of the 

 1

 The ’879 application’s independent claim, as originally filed, read as follows: 

Moldable material for fuel system components for 

communicating fuel to the engine of a motor vehicle, said 

motor vehicle having a common electrical plane maintained 

at a common electrical potential, said material comprising a 

polymer material having electrically conductive fibers 

distributed randomly throughout the material to provide an 

electrically conductive path through said components 

between the fuel communicated through said components 

and said common electrical plane. 

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electrically conductive moldable material.” In addressing the indefiniteness rejection, 

the patentee deleted the “moldable material for” language so that the claims were 

directed to a “fuel system component.” The patentee also argued that the independent 

claim was not indefinite because, although the specification only referred to fuel filters 

and fuel lines, “it is Applicant’s position that he is entitled to a claim broad enough to 

cover all fuel system components manufactured of the moldable material disclosed and 

claimed in the specification.” While the application was pending, the title of the ’879 

application was changed to “Electrostatically Dissipative Fuel System Component,” 

because, the patentee contended, it “more accurately reflect[ed] the scope of the 

claims.” After an interview between the patentee and examiner, which resulted in the 

“arcing” limitation being added, the claims were allowed and the patent issued. 

Following a reexamination proceeding, the sole independent claim was further amended 

to recite “fuel injection system component” instead of “fuel system component” as the 

subject matter of the claims. 

On October 2, 2002, Honeywell filed suit against ITT/TG for infringement of the 

’879 patent. Claim 1 of the ’879 patent, the patent’s only independent claim, provides 

as follows: 

Fuel injection system component for communicating fuel to 

the engine of a motor vehicle, said motor vehicle having an 

electrical plane maintained at a predetermined electrical 

potential, said fuel system component being made of a 

composite material comprising a polymer having electrically 

conductive fibers distributed randomly throughout the 

material to provide an electrically conductive path through 

said component between the fuel communicated through 

said component and said electrical plane, so that at least a 

portion of the electrically conductive path extends through 

the component to thereby prevent build-up of electrostatic 

charge in the fuel and the resultant arcing which causes the 

05-1407 5
breakdown of the polymer material comprising the fuel 

injection system component. 

The products accused of infringement are “quick connects” manufactured and sold by 

ITT/TG. Quick connects are nut-like structures that join the various components of a 

fuel injection system together, such as a fuel line to a fuel filter. The accused quick 

connects have polymer housing that is interlaced with carbon fiber. ITT/TG denied the 

charge of infringement, and the district court subsequently held a Markman hearing to 

construe various limitations of the ’879 patent, including “fuel injection system 

component” and “electrically conductive fiber.” 

The district court construed the “fuel injection system component” limitation to 

mean “a fuel filter.” In arriving at its construction, the court recognized that the ordinary 

meaning of the term “refers to any constituent part of the fuel injection system of a 

motor vehicle including, for example, fuel filters, fuel lines, and connectors.” Honeywell, 

330 F. Supp. 2d at 878. The court also recognized that the patentee made statements 

during the prosecution of the ’879 and ’084 applications that could be interpreted to 

mean that the scope of the “fuel injection system component” limitation was broader 

than only fuel filters, at least in the patentee’s view. 

Notwithstanding the ordinary meaning or the prosecution history, the court 

determined that the written description clearly limited the “fuel injection system 

component” to a fuel filter, and that the statements in the prosecution history could not 

be used to enlarge the content of the written description. Id. at 882-83. According to 

the court, on several occasions in the written description, the “invention” was identified 

to be only a fuel filter. Id. at 879. Moreover, the court explained, “[t]he entire 

specification of the ’879 patent, as well as the sole drawing, describe the elements and 

05-1407 6
operation of a fuel filter with electrically conductive fibers. No other parts are 

described.” Id. Given the written description, the court concluded that “the patentee 

characterized a fuel filter as the only embodiment of his invention, not merely a 

‘preferred’ version of all possible embodiments.” Id. at 880. 

The district court also construed the claim term “electrically conductive fibers” to 

mean “fibers of a material that conducts electricity, including, without limitation, metal 

and carbon.” Id. at 888. According to the court, that was the ordinary meaning of 

“electrically conductive fibers.” The court gave the term its ordinary meaning despite a 

detailed disclosure in the written description why metal fibers were preferable to carbon 

fibers. Id. at 884. In the court’s view, the disclosure was “not like the clear specification 

language defining the ‘invention’ as a fuel filter.” Id. The court determined that the 

disclosure distinguishing metal and non-metal conductive fibers merely reflected the 

patentee’s preferred embodiment. Id. at 884-85. The court further noted that the 

written description never stated that carbon fibers could not be used as electrically 

conductive fibers. Id.

After the court issued its claim construction, ITT/TG filed a motion for summary 

judgment of noninfringement, which the court granted. In concluding that the accused 

products did not infringe the ’879 patent, the court determined that quick connects are 

not fuel filters, and thus they do not literally infringe. Honeywell Int’l, Inc. v. ITT Indus., 

Inc., Civ. No. 02-73948, slip op. at 9 (E.D. Mich. May 17, 2005). Moreover, the court 

found that quick connects do not infringe under the doctrine of equivalents because they 

are not interchangeable with a fuel filter, and they do not compete commercially with 

fuel filters. Id. The also court determined that Honeywell could not invoke the doctrine 

05-1407 7
of equivalents to encompass the accused quick connects in view of the written 

description’s identification of a fuel filter as “the present invention.” According to the 

court, the patentee knew of fuel system components other than fuel filters, and that 

because he limited the claims to a fuel filter, all other fuel system components were 

dedicated to the public, and thus outside the reach of the doctrine of equivalents. Id., 

slip op. at 13-14. 

The district court entered final judgment on April 27, 2005. Honeywell timely 

appealed, and we have jurisdiction pursuant to 28 U.S.C. § 1295(a)(1). 

DISCUSSION 

We review a district court’s grant of summary judgment de novo, reapplying the 

same standard used by the district court. Ethicon Endo-Surgery, Inc. v. U.S. Surgical 

Corp., 149 F.3d 1309, 1315 (Fed. Cir. 1998); Stratienko v. Cordis Corp., 429 F.3d 592, 

597 (6th Cir. 2005). Summary judgment is appropriate if there is no genuine issue as to 

any material fact and the moving party is entitled to a judgment as a matter of law. Fed. 

R. Civ. P. 56(c). “The evidence of the non-movant is to be believed, and all justifiable 

inferences are to be drawn in his favor.” Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 

255 (1986). Claim construction is an issue of law, Markman v. Westview Instruments, 

Inc., 52 F.3d 967, 970-71 (Fed. Cir. 1995) (en banc), that we also review de novo, 

Cybor Corp. v. FAS Techs., Inc., 138 F.3d 1448, 1456 (Fed. Cir. 1998) (en banc). 

I. 

On appeal, Honeywell argues that the district court erred by limiting the “fuel 

injection system component” limitation to a fuel filter and including no other component 

of a fuel injection system. In doing so, Honeywell contends that the court imported a 

05-1407 8
limitation from the specification into the claims and thereby improperly limited the scope 

of the claims to the specification’s preferred embodiment. According to Honeywell, 

nothing in the specification explicitly limits the claim term to a “fuel filter.” Honeywell 

relies on a statement contained in the specification referring to “the metallic components 

used in prior art systems,” ’879 Patent, col.1 ll.32-33, to argue that the term 

“component” was meant to be broad. It also cites the patent’s abstract, which 

summarized the invention using the term “component,” and the title of the patent as 

amended, to further argue that the specification did not limit the “fuel injection system 

component” to a fuel filter. 

In addition, Honeywell points to the prosecution history in assigning error to the 

district court’s construction of the “fuel injection system component” limitation. 

According to Honeywell, the patentee stated during prosecution that the intended scope 

of the claims was to include “all fuel components manufactured of the moldable material 

disclosed and claimed in the specification.” Honeywell also notes that the patent 

examiner issued a restriction requirement during prosecution of the ’084 application 

(which also included claims to “fuel filters”) because “the fuel system component 

[claims] do[ ] not specifically require that the component be a fuel filter.” 

Mainly reiterating the points made by the district court in its claim construction 

decision, ITT/TG responds that the claim term “fuel injection system component” was 

correctly limited to a fuel filter. ITT/TG also argues, however, that the court erred in its 

construction of the “electrically conductive fibers” limitation. ITT/TG contends that the 

court should have construed that term to include only metal fibers with a high aspect 

ratio, not carbon fibers. According to ITT/TG, the written description compared the 

05-1407 9
properties of metal and carbon fibers, and “disparaged” the use of the latter as an 

electrically conductive fiber. ITT/TG contends that there was a clear disavowal of 

carbon fibers from the scope of the claims. Moreover, because the accused quick 

connects are indisputably made with carbon fibers, ITT/TG asserts that there can be no 

infringement either literally or under the doctrine of equivalents. 

We agree with the district court that the claim term “fuel injection system 

component” is limited to a fuel filter. In Phillips v. AWH Corp., 415 F.3d 1303, 1315 

(Fed. Cir. 2005) (en banc), this court recognized that “claims ‘must be read in view of 

the specification, of which they are a part.’” We further stated that “the specification ‘is 

always highly relevant to the claim construction analysis. Usually, it is dispositive; it is 

the single best guide to the meaning of a disputed term.’” Id. (internal citations omitted). 

Here, the written description uses language that leads us to the conclusion that a fuel 

filter is the only “fuel injection system component” that the claims cover, and that a fuel 

filter was not merely discussed as a preferred embodiment. On at least four occasions, 

the written description refers to the fuel filter as “this invention” or “the present 

invention”: 

This invention relates to a fuel filter for use in the fuel line 

that delivers fuel to a motor vehicle engine. ’879 Patent, 

col.1 ll.8-9. 

According to the present invention, a fuel filter for a motor 

vehicle is made from a moldable material which may be 

safely used in vehicles equipped with electronic fuel injection 

system. Id., col.1 ll.40-43. 

This and other advantages of the present invention will 

become apparent from the following descriptions, with 

reference to the accompanying drawing, the sole Figure of 

which is a cross-sectional view of a fuel filter made pursuant 

05-1407 10
to the teachings of the present invention. . . . Id., col.1 ll.43-

49. 

According to the present invention, an electrically conductive 

path is provided between the fuel within the inlet cavity 42 [of 

the fuel filter] and the [vehicle] body 38. Id., col.3 ll.41-43. 

The public is entitled to take the patentee at his word and the word was that the 

invention is a fuel filter. 

Moreover, the written description does not indicate that a fuel filter is merely a 

preferred embodiment of the claimed invention. The fuel filter was the only component 

of an EFI system that the written description disclosed as having a polymer housing with 

electrically conductive fibers interlaced therein. The only other fuel component 

specifically mentioned in the written description, the fuel line, was not required by the 

patentee to be made of an electrically conductive polymer material, as the claims 

require. See id., col.1 ll.59-60 (stating that the “fuel line may also be made of a nonconductive material”). The written description’s detailed discussion of the prior art 

problem addressed by the patented invention, viz., leakage of non-metal fuel filters in 

EFI systems, further supports the conclusion that the fuel filter is not a preferred 

embodiment, but an only embodiment. Id., col.1 ll.10-25. Given the written 

description’s disclosure, we conclude that the patentee has limited the scope of the ’879 

patent claims to a fuel filter. 

Nor are we persuaded by Honeywell’s argument that the patentee confirmed a 

broader scope of his claims during prosecution. Honeywell relies mainly on the 

patentee’s response to the examiner’s indefiniteness rejection in which he stated that 

the claims cover “all fuel components manufactured of the moldable material disclosed 

and claimed in the specification.” Honeywell places too much weight on that statement, 

05-1407 11
as we find it to be ambiguous and possibly inconsistent with the written description. 

After all, the only fuel component disclosed and claimed in the patent was a fuel filter. 

In any event, such a broad and vague statement cannot contradict the clear statements 

in the specification describing the invention more narrowly. 

We also do not assign much weight to the patent examiner’s restriction 

requirement with respect to claims for a “fuel filter” and a “fuel system component” 

during prosecution of the ’084 application. In making the restriction requirement, the 

examiner did not construe the claim term “fuel system component” or determine its 

meaning in light of the written description. He merely required that the applicant elect 

one aspect of his invention for prosecution without applying it to the specification. 

Nevertheless, even if we were to agree with Honeywell that the patentee clearly 

expressed his intention during prosecution to have the “fuel injection system 

component” limitation include components in addition to a fuel filter, it would not change 

the result in this case. As we determined above, the written description provides only a 

fuel filter that is made with polymer housing and electrically conductive fibers interlaced 

therein. No other fuel injection system component with the claimed limitations is 

disclosed or suggested. Where, as here, the written description clearly identifies what 

his invention is, an expression by a patentee during prosecution that he intends his 

claims to cover more than what his specification discloses is entitled to little weight. 

See Biogen, Inc. v. Berlex Labs., 318 F.3d 1132, 1140 (Fed. Cir. 2003) (stating that 

“[r]epresentations during prosecution cannot enlarge the content of the specification”). 

We disagree, however, with the district court’s construction of the claim term 

“electrically conductive fibers” to the extent that it encompasses carbon fibers. This 

05-1407 12
court has recognized that “[w]here the specification makes clear that the invention does 

not include a particular feature, that feature is deemed to be outside the reach of the 

claims of the patent, even though the language of the claims, read without reference to 

the specification, might be considered broad enough to encompass the feature in 

question.” Scimed Life Sys. v. Advanced Cardiovascular Sys., 242 F.3d 1337, 1341 

(Fed. Cir. 2001). It is true, as the district court noted, that the ’879 patent’s written 

description did not expressly define “electrically conductive fibers,” as it did for “fuel 

injection system component.” Nevertheless, based on the disclosure in the written 

description, which demeaned the properties of carbon fibers, we conclude that the 

patentee thereby disavowed carbon fibers from the scope of the ’879 patent’s claims. 

The written description contains the following disclosure: 

Stainless steel also has the advantage of requiring smaller 

quantities for providing the required conductivity than other 

conductive fillers, such as carbon black. ’879 Patent, col.3 

ll.56-60 (emphasis added). 

Other electrically conductive fillers, such as the

aforementioned carbon, act as stress concentrators and, at 

the relatively high filler loadings required to achieve 

conductivity, restrict the ability of the resin matrix to yield 

under stress. Id., col.4 ll.1-5 (emphasis added). 

Also, stainless steel fibers are ductile and non-rigid unlike

straight or metallized carbon fibers. . . . This allows stainless 

steel fibers to maintain their integrity better during meltprocessing. Id., col.4 ll.5-10 (emphasis added). 

Unlike the non-metallic fibers, stainless steel fibers also do 

not increase mechanical strength or stiffness of the base 

resin significantly. Other metal fibers with high aspect ratios 

can be satisfactorily substituted for stainless steel. Id., col.4 

ll.10-14 (emphasis added). 

05-1407 13
In making the above statements, the patentee informed its readers specifically why 

carbon fibers would not be suitable as “electrically conductive fibers” in the claimed 

invention. If the written description could talk, it would say, “Do not use carbon fibers.” 

There is no other way to interpret the written description’s listing of all the reasons that 

metal fibers fare better than carbon fibers for use in the claimed invention, even though 

both materials are electrically conductive, viz., that metal fibers require smaller 

quantities to achieve the desired conductivity than carbon fibers, create less stress 

concentration, are more ductile, are less rigid, and increase the mechanical strength of 

the polymer housing. Contrary to the district court’s understanding, the written 

description has gone beyond expressing the patentee’s preference for one material over 

another. Its repeated derogatory statements concerning one type of material are the 

equivalent of disavowal of that subject matter from the scope of the patent’s claims. 

In reaching this decision, we reject Honeywell’s argument in support of the 

district court’s construction of “electrically conductive fibers.” Honeywell argues that the 

written description did identify carbon fibers as electrically conductive fibers, and that 

stainless steel fibers were merely preferred embodiments. Honeywell’s argument 

misses the point. It is precisely because the written description has identified carbon 

fibers as electrically conductive, and yet it denigrated carbon fibers’ applicability to the 

claimed invention, that we find a disavowal of that subject matter. Moreover, it is 

irrelevant whether stainless steel fibers are a preferred embodiment of the claimed 

invention. We are not here modifying the district court’s claim construction to limit its 

scope to stainless steel fibers. We only modify it to exclude carbon fibers from the 

scope of the ’879 patent claims. 

05-1407 14
II.

Because Honeywell does not appeal the district court’s judgment of lack of literal 

infringement, we turn to the question whether the accused quick connects infringe under 

the doctrine of equivalents. Even if the district court correctly construed the “fuel 

injection system component” limitation, Honeywell argues that the court erred in finding 

that the accused quick connects do not infringe under the doctrine of equivalents as a 

matter of law. According to Honeywell, although quick connects do not filter fuel like a 

fuel filter, the ’879 claims do not require that the “fuel injection system component” 

perform that function. Honeywell contends that the claims only require that the “fuel 

injection system component” perform the functions of “communicat[ing] fuel to the 

engine of a motor vehicle,” and “provid[ing] an electrically conductive path through said 

component and [the] electrical plane.” Honeywell also asserts that the claims require 

that the only result needed to be achieved is to “prevent the build-up of electrostatic 

charge in the fuel and the resultant arcing which causes the breakdown of the polymer 

material comprising the fuel injection system component.” Because, Honeywell argues, 

the accused quick connects perform these functions in the same way as the fuel filter to 

achieve the same result, there is infringement. 

We agree with the district court that the fuel filter and quick connects are not 

equivalent devices. They are substantially different. The accused quick connects do 

not filter fuel. Once we agree with the district court to construe a fuel system 

component to be a fuel filter, the fuel filter is not merely a limitation of the ’879 patent 

claims. It is central to the patented invention. If one utilizes the conventional 

function/way/result analysis, it is beyond question that the accused quick connects do 

05-1407 15
not perform the function of the fuel filter. Any equivalent of a fuel filter must necessarily 

perform the function of fuel filter—filtering fuel—in order to be an equivalent. As 

Honeywell recognizes in its own brief, “a fuel filter inherently filters fuel.” Honeywell Op. 

Br., at 49. 

Having established that any structure equivalent to a fuel filter must substantially 

perform the function of filtering fuel, we affirm the district court’s judgment of 

noninfringement. Honeywell concedes in its brief, as it must, that the accused quick 

connects do not perform the fuel filtering function. Honeywell Op. Br., at 47. Thus, no 

reasonable trier of fact could find that these two structures are equivalent. Given that 

quick connects do not perform substantially the same function as a fuel filter, there is no 

need for us to conduct a further analysis of the way that the accused products perform 

and the result of that performance. 

We also conclude that the accused quick connects do not meet, either literally or 

under the doctrine of equivalents, the “electrically conductive fibers” limitation as we 

have construed it. There is of course no literal infringement because, as we have held 

and Honeywell has admitted, a quick connect is not a fuel filter. There can also be no 

infringement under the doctrine of equivalents because the accused quick connects use 

carbon fibers, and such fibers were disavowed from the scope of the “electrically 

conductive fibers” limitation, as we have discussed above. See J&M Corp. v. Harley–

Davidson, Inc., 269 F.3d 1360, 1366 (Fed. Cir. 2001) (“The scope of equivalents may [ ] 

be limited by statements in the specification that disclaim coverage of certain subject 

matter.” Dawn Equip. Co. v. Ky Farms, Inc., 140 F.3d 1009, 1016 (Fed. Cir. 1998)). 

05-1407 16
CONCLUSION 

Because the accused quick connects do not meet, literally or equivalently, the 

“fuel injection system component” or “electrically conductive fibers” claim limitations, the 

district court’s grant of summary judgment of noninfringement of the ’879 patent in favor 

of ITT/TG is affirmed. 

AFFIRMED

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