General American Transportation Corp. (“GATC”) appeals from the judgment of the United States District Court for the Northern District of Illinois in which the court held GATC liable for patent infringement, awarded Cryo-Trans, Inc. $8,983,440 in damages, and entered a permanent injunction against GATC. General Am. Transp. Corp. v. Cryo-Trans, Inc., 897 F.Supp. 1121 (N.D.Ill.1995); General Am. Transp. Corp. v. Cryo-Trans, Inc., 893 F.Supp. 774 (N.D.Ill.1995). Because the court correctly held that the patent was not proved invalid, but misconstrued the claims and clearly erred in finding infringement, we affirm in part and reverse in part.
BACKGROUND
Cryo-Trans is the assignee of U.S. Patent 4,704,876, which concerns a “cryogenic” rail-car for transporting frozen foods. Cryogenic railcars use inexpensive carbon dioxide (CO2) as the refrigerant. Conventional refrigerated railcars, on the other hand, employ mechanical refrigeration systems that consume fossil fuels and thus are more expensive to operate.
The cryogenic railcar disclosed in the ’876 patent has an insulated compartment (32) extending lengthwise along the top of the car. A system is provided for filling the compartment with solid carbon dioxide “snow” by injecting liquid CO2 into the compartment under high pressure. The bottom of the compartment contains openings (66) adjacent to each of the car’s side walls (16, 18) and end walls (20, 22). In operation, the compartment is first filled with CO2 snow and then the frozen food products are loaded into the cargo area (26). During transit, the CO2 snow gradually sublimates as CO2 gas, which flows through the compartment’s openings (66) and moves downward along the side walls and end walls, enveloping and cooling the load. Each of the four walls has corrugated channels to facilitate the flow of the CO2 gas down that particular wall. Figure 1 of the patent illustrates the railcar:
*768[[Image here]]
Claim 1 is representative of the asserted claims. It reads, with emphasis on the language in dispute, as follows:
1. In a container adapted to be maintained in a refrigerated condition from the sublimation of carbon dioxide snow[,] the combination comprising:
a storage area defined by a floor, a pair of opposed side walls, a pair of opposed end walls, and a ceiling means;
an insulated roof positioned above said ceiling means and defining therewith a compartment for supporting a supply of carbon dioxide snow, said compartment extending substantially the full length of said storage area;
means in said compartment for forming carbon dioxide snow and means for connecting said carbon dioxide snow forming means to a supply of liquid carbon dioxide;
a plurality of openings through said ceiling means adjacent [sic] each of said side walls and end walls for permitting the flow of sublimated carbon dioxide gas from said compartment;
each of said walls being corrugated to define a plurality of channels therein open-sided toward the interior of the container whereby said carbon dioxide gas may flow from said openings in said ceiling means downwardly through said channels between said walls and a product load disposed in said container toward said floor.
Numerous cryogenic railcars were known before the invention at issue here. The “AFFX 2002” railcar, for example, which was built and publicly used in 1983, embodied all the elements of claim 1 except that its compartment for holding C02 snow had openings adjacent to only one side wall and it had no openings adjacent to the end walls. U.K. Patent 399,678, issued to Kurth in 1933, disclosed a cryogenic railcar in which a compartment for holding solid C02 had openings adjacent to both side walls, but again had no openings adjacent to the end walls. It also had no corrugated walls or system for forming C02 snow using liquid C02.
GATC manufactured a cryogenic railcar that included a compartment for holding C02 snow. The bottom of the compartment had a row of openings provided lengthwise along its center and two rows of openings adjacent to the car’s opposite side walls. The openings adjacent to the side walls were each three inches from the nearest side wall, and the endmost of such openings were three feet from the nearest end wall. The endmost *769center row openings were six feet from the nearest end wall. The drawing below illustrates the arrangement of openings in GATC’s railcar compartment:
[[Image here]]
In March 1991, after Cryo-Trans threatened to assert the ’876 patent against GATC, GATC sued Cryo-Trans seeking, inter alia, a declaratory judgment that the patent was invalid, unenforceable, and not infringed. GATC argued that it did not infringe because the bottom of the compartment in its railcar lacked openings adjacent to the car’s end walls, as required by the claims. Cryo-Trans counterclaimed for infringement of claims 1-3.
The district court conducted a bench trial in May 1995. At the conclusion of the trial, the court, relying on a dictionary definition, construed the term “adjacent” in the claims to mean “not far off’ or “not necessarily at but nearby or near.” The court then found that the endmost openings adjacent to the side walls in GATC’s railcar compartment were “not far” from the ear’s end walls and functioned as openings adjacent to the end walls. Thus, the court found that GATC had infringed the claims, both literally and under the doctrine of equivalents. It rejected GATC’s invalidity and unenforeeability claims. The court accordingly awarded Cryo-Trans $8,983,440 in damages and entered a permanent injunction.
GATC appeals, challenging the district court’s findings that the ’876 patent was infringed and not proved invalid. GATC does not appeal the court’s decision rejecting GATC’s unenforceability claim.
DISCUSSION
A. Infringement
Determining whether a patent claim has been infringed requires a two-step analysis: “First, the claim must be properly construed to determine its scope and meaning. Second, the claim as properly construed must be compared to the accused device or process.” Carroll Touch, Inc. v. Electro Mechanical Sys., Inc., 15 F.3d 1573, 1576, 27 USPQ2d 1836, 1839 (Fed.Cir.1993). Claim construction is a question of law, reviewed de novo on appeal. Markman v. Westview Instruments, Inc., 52 F.3d 967, 979, 34 USPQ2d 1321, 1329 (Fed.Cir.1995) (in bane), aff'd, — U.S. -, 116 S.Ct. 1384, 134 L.Ed.2d 577 (1996). The application of the claim to the accused device is a question of fact, reviewed for clear error. Mannesmann Demag Corp. v. Engineered Metal Prods. Co., 793 F.2d 1279, 1282, 230 USPQ 45, 46 (Fed.Cir.1986).
GATC argues that the district court misconstrued the claim language “openings through said ceiling means adjacent to each of said side walls and end walls,” which led to a clearly erroneous finding of infringement. We agree. As explained below, the district court incorrectly held that openings “adjacent” to the side walls could also be considered to be openings “adjacent” to the end walls. That error led to a clearly erroneous finding of infringement.
To ascertain the meaning of the claims, we consider the claim language, the specification, and the prosecution history. Markman, 52 F.3d at 979, 34 USPQ2d at 1329. Here, the claim language itself distin*770guishes between the openings that are adjacent to the side walls and those that are adjacent to the end walls. Specifically, the claims require “openings ... adjacent each of said side walls and end walls,” which suggests that the openings adjacent to the side walls are structurally distinct from the openings adjacent to the end walls. The district court’s claim construction obliterated that distinction.
In addition, the patent specification distinguishes between the openings that are adjacent to the side walls and those that are adjacent to the end walls. It states, in the “Summary of the Invention” section, that “[t]he bottom of the compartment is provided with openings along each side and end wall of the car through which sublimating carbon dioxide gas may escape.” Col. 2, 11. 22-25 (emphasis added). Similarly, the “Detailed Description of the Invention” portion of the specification states:
The bottom wall 40 of the compartment 32 is provided with a plurality of openings 66 along each of the side walls 16, 18 and along each end wall 20, 22 of the car and which openings are preferably slanted toward the adjacent wall. These openings are provided for the flow of carbon dioxide gas sublimating from the snow contained within the compartment 32 and which gas may then flow downwardly along the adjacent wall through the sinusoidal passageways defined thereby. The openings on opposite walls preferably are offset with respect to each other.
Col. 3, 11. 41-51 (emphasis added). This arrangement of openings is said to yield an advantage: “[Bjecause the cold carbon dioxide gas is flowing downwardly on each of the opposite sides and on the ends of the car and in direct contact with the bottom of the load, all parts of the load will be maintained at a desirably low temperature.” Col. 5,11. 59-64 (emphasis added). Figure 1, to which the detailed description refers, depicts separate openings (66) adjacent to each of the side and end walls. Carbon dioxide gas is shown exiting each opening and travelling down the nearest wall.
Thus, the specification and drawings teach that the openings are provided along all four walls, and that each opening directs the flow of C02 gas down a particular, “adjacent” wall, i.e., the nearest wall. This is not just the preferred embodiment of the invention; it is the only one described. Nothing in the claim language, specification, or drawings suggests that any of the dedicated side or end wall openings may be eliminated, or that an opening may be “adjacent” to more than one wall. The prosecution history is brief and not helpful to resolving the meaning of the disputed claim language.
Under these circumstances, we construe the phrase “openings ... adjacent each of said side walls and end walls” as referring to structurally distinct openings that are provided adjacent to each of the railcar’s four walls. Each opening is “adjacent” to only one wall, the nearest one to which it directs the downward flow of C02 gas. Thus, an opening “adjacent” to a side wall cannot also be an opening “adjacent” to an end wall. The patent does not contemplate the openings performing double duty in this manner. We therefore reject the district court’s claim construction, which was inconsistent with the specification and drawings and rendered superfluous the claim requirement for openings adjacent to the end walls.
In GATC’s railcar, the openings were all closest to and thus “adjacent” to the side walls. The endmost openings are in fact twelve times the distance to the end walls compared with their distance to the side walls. The car lacked “a plurality of openings ... adjacent each of said ... end walls,” as required by the properly construed claims. We therefore hold that the district court clearly erred in finding literal infringement of claim 1 and dependent claims 2-3. See Johnston v. IVAC Corp., 885 F.2d 1574,1580, 12 USPQ2d 1382, 1386 (Fed.Cir.1989) (“Where a claim does not read on an accused device exactly, there can be no literal infringement.”); Mannesmann Demag Corp., 793 F.2d at 1282, 230 USPQ at 46 (literal infringement requires that every element of the patent claim be met).
Furthermore, the district court’s finding of infringement under the doctrine of equivalents was also clearly erroneous, for two reasons. First, the finding violated the *771principle that the doctrine may not be used to expand the scope of the patentee’s right to exclude so as to encompass the prior art. E.g., Key Mfg. Group, Inc. v. Microdot, Inc., 925 F.2d 1444, 1449, 17 USPQ2d 1806, 1810 (Fed.Cir.1991). Here, the AFFX 2002 rail-car had all the elements of claim 1 except that its compartment for holding CO2 snow had openings adjacent to only one side wall and it had no openings adjacent to the end walls. This design was known to be deficient because “hot spots” (areas of thawing) tended to form in the eargo area opposite the side where the C02 gas was introduced. Clearly those of ordinary skill in the art would have known that insufficient CO2 gas was reaching this area. Thus, it would have been obvious to more uniformly cool the entire cargo area by providing openings along both side walls. The Kurth patent, in fact, disclosed a cryogenic railcar in which the compartment for holding the solid 002 had openings adjacent to both side walls. The AFFX 2002 and Kurth railcars were in the same field of endeavor as the claimed invention and were properly combinable prior art. The Kurth patent was not before the PTO during the prosecution of the ’876 patent.
We are therefore convinced that the prior art fairly suggested a cryogenic railcar having the combination of features present in GATC’s railcar, including a compartment having openings adjacent to both of the car’s side walls. Thus, since allowing the claims to encompass GATC’s car would cause the claims to cover subject matter obvious over the prior art, the car cannot be held to infringe the ’876 patent under the doctrine of equivalents. See Wilson Sporting Goods Co. v. David Geoffrey & Assocs., 904 F.2d 677,14 USPQ2d 1942 (Fed.Cir.), cert. denied, 498 U.S. 992, 111 S.Ct. 537, 112 L.Ed.2d 547 (1990). As we stated in Wilson Sporting Goods:
[A] patentee should not be able to obtain, under the doctrine of equivalents, coverage which he could not lawfully have obtained from the PTO by literal claims. The doctrine of equivalents exists to prevent a fraud on a patent, not to give a patentee something which he could not lawfully have obtained from the PTO had he tried. Thus, since prior art always limits what an inventor could have claimed, it limits the range of permissible equivalents of a claim.
Id. at 684, 904 F.2d 677, 14 USPQ2d at 1948 (citation omitted); see also Stewart-Warner Corp. v. City of Pontiac, Michigan, 767 F.2d 1563, 1572, 226 USPQ 676, 682 (Fed.Cir.1985) (there can be no infringement under the doctrine when “the asserted range [of equivalents] would encompass the prior art at the very point at which the ... claims distinguish from that prior art”).
Second, the district court’s finding of infringement under the doctrine of equivalents was clearly erroneous because “[t]here can be no infringement as a matter of law if a claim limitation is totally missing from the accused device.” London v. Carson Pirie Scott & Co., 946 F.2d 1534, 1539, 20 USPQ2d 1456, 1459 (Fed.Cir.1991). GATC’s railcar had no openings adjacent to the end walls, as required by the claims, nor did GATC substitute an equivalent structure. Cryo-Trans argues that its expert testified that “the endmost vents of the center row will provide a substitute for any ceiling vents eliminated by GATC.” We disagree with Cryo-Trans that each of the endmost center row openings, located six feet from the nearest end wall, was equivalent to a “plurality” of openings adjacent to the end walls. They are much further from the end walls than the endmost openings in the side walls, which we have held do not satisfy the claim limitation. Thus, because the accused device lacked an equivalent to “a plurality of openings ... adjacent each of said ... end walls,” there was no infringement under the doctrine of equivalents. See London, 946 F.2d at 1539, 20 USPQ2d at 1459; Pennwalt Corp. v. Durand-Wayland, Inc., 833 F.2d 931, 937, 4 USPQ2d 1737, 1741 (Fed.Cir.1987) (in banc) (“A device that does not satisfy [a] limitation at least equivalently does not function in substantially the same way as the claimed invention.”), cert. denied, 485 U.S. 961, 108 S.Ct. 1226, 99 L.Ed.2d 426 (1988); Perkin-Elmer Corp. v. Westinghouse Elec. Corp., 822 F.2d 1528, 1532, 3 USPQ2d 1321, 1324 (Fed.Cir.1987) (courts may not “convert a multi-limitation claim to one of [fewer] limitations to support a finding of equivalency”).
*772Accordingly, we reverse the district court’s findings of literal infringement and infringement under the doctrine of equivalents.
B. Validity
GATC argues that “[i]f the district court’s claim construction is correct, then the ’876 Patent is invalid” under 35 U.S.C. §§ 102 and 103. GATC contends, inter alia, that if claim 1 were construed to cover a railcar that had no openings adjacent to the end walls, the combination of the AFFX 2002 railcar with the Kurth patent would render the claim invalid for obviousness.
We have agreed with GATC, however, that the district court’s claim construction was not correct. Thus, its obviousness argument directed to that claim construction is no longer pertinent. GATC has not argued or established that the prior art would have rendered obvious a cryogenic railcar having a compartment that included openings adjacent to all four walls, as required by the properly construed claims. We decline to speculate whether it would have been obvious to those of ordinary skill in the art to modify the AFFX 2002/Kurth railcar by adding openings adjacent to the end walls. Thus, the district court did not clearly err in concluding that GATC did not prove invalidity by clear and convincing evidence.
We have considered the parties’ remaining arguments but find them either unpersuasive or unnecessary for resolution of the appeal. Among these arguments is GATC’s claim of prior invention by James Moe and Tom Maxwell. Moreover, in view of our conclusion concerning infringement, we must vacate the award of damages and the permanent injunction. GATC’s arguments concerning the correctness of the damages award are therefore moot.
CONCLUSION
The district court erred as a matter of law in construing the claims and clearly erred in finding infringement. Accordingly, the court’s decision finding infringement, awarding damages, and entering a permanent injunction is reversed. Its conclusion concerning validity is affirmed.
COSTS
No costs.
AFFIRMED-IN-PART AND REVERSED-IN-PART.