US1563315A - Fuel-injecting device for internal-combustion engines - Google Patents

Description

Dec. 1,1925. I 1,563,315 I 0. ALT" ET AL FUEL INJECTING DEVICE FOR INTERNAL COMBUSTION ENGINES Filed March 27, 1922 Fig.4. Fig.2.

Patented Dec. 1, 1925.

UNITED S ATES PATENT. orrlcli.

OTTO ALT'AND GURT HFLSIG, OF KIEL, GERMANY, ASSIGNORS TO FRIED. KRUPP .AKTIENGESELLSCHAFT GERMANIAWERFT, F KIEL-GAARDEN, GERMANY.

FD'EL-INJ'ECTING DEVICE FOR INTERNAL-COMBUSTION ENGINES.

Application filed March27, 1922. Serial No. 547,323.

To all whom it may concern:

Be it known that we, O'r'ro ALT, residing at Kiel, Germany, and CURT HnLsTo, residing at Kiel, Germany, both citizens of the Republic of Germany, have invented a certain new and useful Improvement in Fuel- Tnjectin'g Devices for Internal-Combustion Engines, of which the following is a speci- 'fication.

This invention. relates to fuel injecting devices for internal combustion engines and has more particularly reference to injecting devices of the kind in which, upon opening a needle valve, the fuel is atomized and carried into the engine cylinder by acurrent of highly compressed injecting air which flows past the outlet of the fuel chamber.

In the drawings: Fig. 1 is a partial longitudinal section through a fuel injecting device constructed in accordance with .theinvention;

Fig. 2 is a similar section through a modifiedform of the invention. 1

Referring first to Fig. 1 off the drawings, the device comprises a ---.valve cageA in which is mounted a sleeve B which receives the valve needle 0. The sleeve B is of a shape such asto form" an annular room F between itself and the. valve needle C and 3. annular rooms D and G between itself and the wall of the valve-cage A. The annular rooms D and F are in connection with each other by bores E. The intermediate portion of the sleeve B is enlarged and forms a shoulder separating the room D from the room G. The wall of the valve cage A has a shoulder corresponding to the shoulder of the sleeve B. A packing ring H mounted between the said two shoulders provides for an air-tight'joint between thesleeve B and the wall of the valve cage A. The lower end of the sleeve B has the shape of a cone b which between itself and the valve needle C leaves an annular-passage J which is subdivided by narrow longitudinal ribs pro L by means of the fuel pump (not shown) will -fill the lower part of the annular room G and will also partially enter into the annular passage K. The annular rooms D and F contain compressed injecting air, the pressure of which is higher than the pressure at the end of, the compression in the engine cylinder. The portion of .the annular room G which isnot filled out with fuel, will serve as an air-chamber. When the valve is closed said air-chamber contains a column of air which has assumed the same pressure as the compressed injecting air, said column of air being completely separated from the compressed injecting air by the fuel contained in the lower portion of the room G. The volume of the said air-chamber must be such that the degree of ex ansionvof the air contained therein wil at least be sufficient to press the quantity of fuel, which is fed by the fuel pump when the engine is working at full load. into the jet of injecting air when the needle valve is opened. a

Upon opening the needle valve 0, the compressed iniecting air flows through the annular passage J into the cylinder. It rushes past the outletof the annular passage K and produces a vacuum in the same. At the same time the column of air contained in the annular room G expands and drives the fuel through the annular passage K into the jet of compressed injecting air.

If the annular room G is of suitable dimensions, the entering of the fuel into the cylinder will not take place suddenly because of the rapid decrease of the ressure of the column of air contained in t e room (Jr above the fuel, but the fuel will enter the cylinder with a certain retardation. Besides, as already mentioned, the quantity of. air contained'in the air-chamber needs only be so large that, when the engine is working at full load, the maximum quantity of fuel fed by the pump will justbe pressed into the jet of injecting air, so that afterwards the air in the air-chamber will be entirely expanded.

Fuel injecting devices are now in use in which the air of injection is divided into 1 two branches within the nozzle, the fuel being driven forward by the air in one branch 7 and atomized in the other branch. In com-.

parison with these well-known fuel injecting tial advantage that, especially when the engine is Working at low loads and therefore necessitates only small quantities of fuel, no subsequent flowing-in of air of importance will take place after the period of fuel-injection hassbeen finished. ,Moreover, since the room G will always contain substantially the same air which is alternately compressed and expanded in the same manner as the air of the well-known air-chambers, the portion of said air which might still flow after the fuel will be hi hly heated which will be of afavorable influence on the process of combustion.

The modification illustrated by Fig. 2 deviates from the construction hereinbefore described inasmuch as means are provided for changing the volume of the room G. These means comprise an adjustable internally threaded -collar N which may be screwed up and down on the sleeve B which is provided with external threads on the ortion situated in theroom G. An air tight joint is formed between thecollar N and the wall of the valve cage A by means of a packing ring a which is mounted in an annular dove-tailed groove of the collar N. The cone 6 is removably fastened to the sleeve B for the purpose of allowing the collar N to be mounted on the sleeve B. This type of atomizer is preferably used for determining the volume of the annular room G in engines of a new type or it may be successfully applied to engines designed to be driven by heavy as well as by light fuels.

Claims: 1

1. In a fuel injector for internal combustion engines, a fuel chamber, a fuel inlet and an injecting air inlet communicating with said chamber, and means whereby air is trapped in said chamber by the fuel charge and compressed in dependence upon the pressure of the injecting air, the charge being expelled from said chamber under the expansive force of said air upon the operation of the injector.

2. Fuel injector for internal combustion engines comprising a valve for controlling a cylinder inlet, a fuel chamber, and an air pressure chamber, said chambers being 1n v connection only by respective outlet channels confluent at the cylinder inlet, said fuel chamber being entirely closed above the level of the fuel therein whereby an air cushion is formed above said fuel level.

3. In combination with an internal combustion engine cylinder, a valve cage, a valve needle mounted therein, a port in said cylinder controlled by said needle, a fuel chamber, achamber containing air under pressure, a passage communicating between said fuel chamber, said air chamber and said cylinder port, said fuel chamber being entirely closed above the level of the fuel therein whereby said cylinder port being closed an air cushion is formed in said fuel chamber, said air cushion tending to expel the fuel from said fuel chamber with a force balanced by the contrary force existing in said air chamber, and-means whereby said cylinder port being opened fuel is expelled from said fuel chamber by the expanding action of said air cushion and delivered to said combustion cyllnder under the combined influence of said expanding action and said air under pressure.

4. A fuel injecting device for internalcombustion engines, comprising in combination a valve cage, a needle valve, a fuel room and a room for compressed injecting air, an air-chamber formed in connection with said fuel room, said air-chamber being entire] closed and situated in the interior -of t e device, and means for varying the' volume of said air-chamber, the air contained in said air-chamber being adapted to expand and to press the fuel into the jet of compressed injecting air when the needle valve is opened, and to assume again the pressure of the injecting air when the needle .valve has been closed.

ing air tight above the level of the fuel therein whereby an air chamber is formed above said fuel level, the air contained in said air-chamber being adapted to expand and to press the fuel into the jet of compressed injecting air when the needle valve is opened,

and to assume again the pressure of the injecting air when the needle valve has been closed.

6. A fuel injecting device for internal combustion engines, comprising a valve cage and a valve needle mounted therein, a cylindrical sleeve also mounted in said valve cage and concentrically surrounding the valve needle, two annular rooms being formed between the cylindrical sleeve, the valve cage and the valve needle, one room containing fuel and the other room-containing compressed injecting air, both rooms having coinciding outlets, and air contained in the first-mentioned room above the fuel, this room being larger than is necessary for the reception of the fuel and air tight above the level of the fuel therein so that, upon opening the needle valve,'the expansion of the air above the fuel will at least suffice to press the quantity of fuel which is fed into said room when the engine is working at full load, into the jet of compressed air leaving the room containing the same.

7. A fuel injecting device for internal combustion engines, comprising a valve cage and a valve needle mounted therein, a cylindrical sleeve also mounted in said valve ca e and concentrically surrounding the va ve needle, 21 room for receiving fuel and aroom for receiving compressed injecting air being formed by the cylindrical sleeve, the valve cage and the valve needle, the fuel room forming at the sametime an air-chamber, and the said cyhndrlcal sleeve having an externally screw-threaded portion situv ated in the said air-chamber, an internally threaded collar adjustably mounted on said threaded portion of the cylindrical sleeve,

and means on said collar for providing an air-tight joint between the collar and the wall of the valve cage.

- .OTTO' ALT.

CURT HELSIG.

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