Stromberg Motor Devices Co. v. Zenith-Detroit Corp.

25 F.2d 567, 1928 U.S. App. LEXIS 3012
CourtCourt of Appeals for the Second Circuit
DecidedApril 16, 1928
DocketNo. 159
StatusPublished
Cited by3 cases

This text of 25 F.2d 567 (Stromberg Motor Devices Co. v. Zenith-Detroit Corp.) is published on Counsel Stack Legal Research, covering Court of Appeals for the Second Circuit primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Stromberg Motor Devices Co. v. Zenith-Detroit Corp., 25 F.2d 567, 1928 U.S. App. LEXIS 3012 (2d Cir. 1928).

Opinion

MANTON, Circuit Judge.

This suit is for infringement of patent for a carburetor used to supply an internal combustion engine with a proper fuel mixture for the operation of the engine. The claim sued upon reads:

“4. In a carburetor, a carbureting chamber having a mixture outlet, a venturi tube leading to said carbureting chamber, a second venturi tube leading into said first named venturi tube, said venturi tubes having their axes substantially coincident and having air inlets thereto, a fuel inlet leading into said second venturi tube, and means for admitting air to said fuel inlet anterior to its point of discharge into said second venturi tube.”

The principal functions of this carburetor are (a) as operated by suction created by the engine it draws atomized gasoline and air into the carbureting chamber and there intermixes them and passes the mixture into the engine; and (b) it automatically varies the richness of the mixture under varying conditions of speed, so that air and atomized fuel shall be in the proper proportions to secure the best results under different conditions in the engine.

There is a tendency for the mixture supplied by a carburetor to become richer— that is, to have a larger proportion of gasoline than air — as the speed of the engine and consequently the suction created by the engine and operative on the carburetor increases. It is essential for the successful operation of the internal combustion engine that this tendency be counteracted or compensated for, and there have been many inventions directed to that end. A carburetor consists generally of a constant level gasoline chamber in which the gasoline is fed to a nozzle which opens into a venturi tube, the inlet to which is opened so that air drawn by the suction of the engine may be drawn through the inlet, past the nozzle, into the mixing chamber, through an outlet into the engine. The gasoline stands below the level of the nozzle outlet, and the vacuum created by the suction of the engine is satisfied in part by the air flowing through the venturi tube and in part by the gasoline flowing from the nozzle whereby the gasoline is drawn into the mixing chamber in a spray which is mixed with air, which has been drawn through the air inlet of the venturi tube, in the normal volume in most eases 16 of air to 1 of gasoline by weight, and in this highly atomized and attenuated state, the mixture is drawn into the cylinder of the engine where it is ignited by explosive expansion and furnishes the power for the operation of the engine.

At the time of the conception of the patent in suit, there were different methods of counteracting or compensating for the tendency to increase richness as the speed of the engine increased. Krebs’ invention, of the prior art, provided a carburetor which had a main air inlet with an auxiliary air iruet so closed by a spring pressed valve, that when the suction increased sufficiently to overcome the resistance of the spring, the valve would open, thus admitting additional air. It went into extensive use up to 1915. Another method of compensating fop this tendency toward increased richness as suction increased was by admitting air to the fuel inlet anterior to its point of discharge [568]*568into the venturi tube', referred to as “air bleeding.” This differed from Krebs’ ,in not requiring the moving of parts peculiar to his, but embodied the idea of a plain tube, carburetor. An auxiliary well was added to the rudimentary carburetor in which gasoline collected when the engine was idle and from which the collected gasoline was drawn when the engine suction was applied. After the gasoline collected was withdrawn, air was drawn through the auxiliary well, which thus satisfied the suction and so tended to counteract the tendency to overriehness with increased suction.

In the patent in suit, there is a single fuel stream whereas in the appellee’s device a compound nozzle is built. The air-bled carburetor was known as in the Ahara patent No. 684,662 granted in 1901. With a car•buretor in which there is a single flow of gasoline through a single channel, the air bled into the gasoline flow to counteract the tendency to overriehness at high speeds mingles -with the entire flow of gasoline, and, in the carburetor in which there is a divided flow of gasoline through two channels, the air drawn into the gasoline flow to counteract the tendency to overriehness at high speed may be bled into one channel only, and in that case it mingles first with the gasoline in the channel, but later, at a joint inlet in the venturi tube, it mingles with the entire flow from both channels, and the air coming through the main air inlet constitutes the whole mixture supplied to the engine of a proper proportion of air and gasoline at all speeds. There is no difference, in so far as diluting the entire gasoline supply with air is concerned, between bleeding the air into the whole of an undivided gasoline stream and bleeding the same amount into one part of divided gasoline stream where the parts immediately reunite. It has been held that both forms embody the Abara air-bleeding invention. Stromberg Motor Devices Co. v. Zenith Carburetor Co. (C. C. A.) , 254 F. 68.

The patent in suit has a mixing chamber with an outlet into a manifold leading into the engine. The throttle valve is adapted to vary .the area of the mixture outlet. There are two venturi -tubes coaxially arranged. Each has an air inlet ■ branching from the main air inlet. The main venturi leads directly to the carbureting or mixing chamber, and the second venturi leads into the main venturi. In the second venturi, a fuel' inlet leads by multiple openings and that fuel inlet is provided with an air inlet through the opening by an annular channel around the venturi tube leading by the opening to the annular space and then by an opening to the fuel inlet passage. The advance made in the use of the internal combustion motor transportation is said to be due largely to the beneficial results flowing from the improvements in carburetors. Economy secured by a proper proportioning of the air and gasoline, as required by the engine under different conditions of load and speed, 'requires much refinement in preparing and supplying the engine with a’ proper mixture of gas. The gist of the invention in suit is the combination of a coaxial double venturi with a fuel inlet which leads into the inner, one and which has means 'for the admission of air thereto anterior to its point of discharge therein, be that fuel inlet single or compound. The range of equivalents for the invention, which includes the air-bled fuel inlet disclosed by the Ahara patent of a divided stream flow of fuel as in the appellee’s compound nozzle carburetor and the single stream flow of the appellant’s single nozzle carburetor is claimed to be manifest and an inevitable identity in kind of result because with a single stream flow the air-bleed can be made such as to give every possible range of richness or mixture from no air at all to all air possible, and, with the divided stream flow, the range that is possible must lie somewhere between these two extremes from no air at all toward or in the direction of all air possible, and thus it must coincide with a part at least of the total range possible with the single stream fuel flow.

This construction has realized in practice' important advantages, such as giving richer mixture at low speeds and much desired greater power, and counteracting more satisfactorily and advantageously toward richness of mixture at high speed, both of which work economy. It atomizes the gasoline more finely, and makes a better intermix with an air column than before.

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Bluebook (online)
25 F.2d 567, 1928 U.S. App. LEXIS 3012, Counsel Stack Legal Research, https://law.counselstack.com/opinion/stromberg-motor-devices-co-v-zenith-detroit-corp-ca2-1928.