Title:
Injection nozzle
United States Patent 2264914


Abstract:
The present invention relates to injection nozzles for internal combustion engines operating on light oil. Injection nozzles for volatile fuel frequently fail in the case of heavily thermally loaded engines soon after starting the engine or after a short operating period on account of the...



Inventors:
Rudolf, Orange L.
Application Number:
US19962138A
Publication Date:
12/02/1941
Filing Date:
04/02/1938
Assignee:
Rudolf, Orange L.
Primary Class:
Other Classes:
123/41.31, 239/533.7, 239/590.3
International Classes:
F02M53/04; F02M53/08; F02M61/08; F02M61/14
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Description:

The present invention relates to injection nozzles for internal combustion engines operating on light oil.

Injection nozzles for volatile fuel frequently fail in the case of heavily thermally loaded engines soon after starting the engine or after a short operating period on account of the fact that the injection nozzles become heated. Hitherto such injection nozzles have been cooled in a similar manner as for crude oil and Diesel engines, that is to say by the cooling agent provided for the engine cylinder itself and thus in most cases by cooling the surrounding walls with water or other liquid cooling agent or with air.

These cooling agents were sufficient so long as only oil of a fairly high boiling point was used.

Many experiments have shown, however, that it is very difficult to cool the cylinder head and the injection nozzle located therein to temperatures below 60°. This, however, is necessary in the case of volatile fuels in order to prevent the formation of gas bubbles and thence a faulty operation of the injection system and missing of the engine.

In connection with this necessary low temperature the hitherto so-called "cold transmitting" agents are in reality "heat transmitting" agents.

The present invention is based on this fact and consists in that the injection nozzle is protected by means of insulation from the cylinder head side walls, hitherto considered as a cooling agent, and also in that the low temperature of the light oil itself is used for cooling the nozzle.

Thus, according to the present invention the fuel is led to the nozzle in as cold a condition as possible, and is protected therein from any heating by conduction or radiation from the engine cylinder.

The means used for this purpose consist firstly in a highly efficient insulation of the whole fuel Spath in and on the cylinder, and secondly, in decreasing to the minimum possible the quantity of S fuel located in this region.

Due to the latter means a rapid change of the fuel in this region is effected so that there is no time available for absorbing heat but the newly arriving fuel always sufficiently cools the fuel still remaining.

In the accompanying drawing, Fig. 1 shows in section such a nozzle which is formed in the known manner as an open injection nozzle with a simple check non-return valve, Fig. 2 shows in section a nozzle with external valve spring, Fig. 3 shows in section a nozzle with its orifices set in a predetermined direction, and Figs. 3a and 3b show two forms of a detail of Fig. 3.

In Figure 1 a is a part of the cylinder or cylinder cover of a fuel injection engine operating on light oil. b is the actual injection nozzle provided with atomizing orifices h to which the fuel arrives through the bore g which is made as narrow as possible. Above said bore is provided a simple check non-return valve e seated in a union member c. The whole nozzle body is constrained on its seat k by means of the securing screw d.

The atomizer part b is protected from the cylinder walls by insulation I which may consist of asbestos, mica or any other suitable material, and for practical reasons the insulating material is held together by means of an insulating protecting sleeve t. The heat absorbing surface of the atomizer part b and the upper surface of the fuel space located therein is reduced to the minimum possible.

In order to render still more difficult heat transmission from the cylinder to the injection nozzle the insulating protecting sleeve t is not located directly on the cylinder walls but an air space is arranged between, and it is especially provided that the air in said space after becoming heated can flow away through apertures I in the holding screw.

In the connecting member c is fitted a filter cartridge m formed in one piece. The fuel passes into this through the axial central aperture, thence through radial apertures 7 into the filter ring space 8, the dimension of which is adjusted according to the fineness of the filter. Particles which have greater dimensions than that of the filter apertures in the space 8 are retained here.

From 8 the fuel again flows back into the main central channel through the radial apertures 9.

The insulating air layer hereinabove described provides in a very complete manner the insulation for the nozzle cooled by the fuel, Fig. 2.

Between the nozzle body a and the cylinder walls a is provided an ample air insulating space y which is in communication with the outer air through the slit I formed in the screw thread.

By means of an aperture i, which may for example be connected to the suction pipe, this air is continuously renewed so that an efficient insulating agent is thus formed between the injection nozzle cooled by the fuel and the cylinder walls.

Furthermore, in this embodiment the check non-return valve e is formed with an externally located spring and the atomizer part t- in the nozzle body u is screwed in from below. Similar to the securing screw in the preceding example, in this case the nozzle body u carries the heat radiating surfaces v.

In Pig. 3 is shown, similar to Fig. 1, an embodiment wherein the atomizing orifices h are set in a determined direction by means of prismatic guides w.

In this case the heat insulation is provided in that in the somewhat larger atomizer part b is I inserted a filler tube x. This simple form of insulation is based on the observation that the surface resistance to heat transmission is very considerable, and can replace an insulation of substantial thickness. The inner tube x is there- 1 fore inserted so firmly that it remains seated in its aperture without any further securing means, but it is however provided with a certain thin insulating layer on its outer surface either by oxidation, or a very fine layer of graphite or carbon, 2 or by being moistened with water glass before its insertion. It may also be provided with a slightly turned part or annular ring, but care must, however, be taken that this is so well sealed off above and below from the light oil, or is so firmly 2: packed with insulating material, that any moistening with fuel is prevented.

The outer end of the tube x may be adapted to act as a stop for the check non-return valve e which is, in this case, formed as a ball valve. so In addition to the heat insulation described above there is also provided in this case an additional insulation by specially increasing the air space y which is aerated through the apertures i.

In one specially practicable form the air insulating space y in the present example is formed in such a way that the part of the atomizing member b outside the seat c of the injection nozzle has a smaller diameter than that of the nozzle seat itself, so that in this way without any further increase in dimensions an ample heat insulating air layer is former. In this example the nozzle holding screw is screwed against the nozzle holder z which is provided with the above-mentioned aerating orifice i, and which in its turn is screwed in the cylinder a.

Furthermore, in this example, a filter cartridge is provided in the connecting part c consisting of the screw threaded member q, the tubular member m provided with an inclined slot and the filter o. The filter consists of lead having very fine perforations or wire gauze, but preferably of a combination of fine wire sieves on the outer side and coarse gauze sieves on the inner side, capable of acting as a support. The elements q, m and o may be advantageously formed together as a common cartridgelike member.

The outer fine gauze is advantageously made finer than the diameter of the nozzle apertures ca so that at this place those impurities of the fuel which were originally in the injection pump or which penetrate into the fuel by scaling off from the pressure conduits, are retained.

By means of the stepped construction of the 03 wire sieves according to the present invention an extension of the fuel space and thence an increase in its surface is completely avoided and also any return of the fuel which is prejudicial in the case of the high liquid velocity desired, is prevented. By the length of the sieves it is easy to make the section of passage as great as desired without appreciably varying the diameter of the tube.

In the embodiment of Pig. 3, since the atomiser 3 nozzle is fixed by the guides w special arrangements of atomiser orifices may be provided. For injection perpendicular or approximately perpendicular to the cylinder axis it is especially advanStageous to arrange the atomiser orifices in oval form adapted according to the existing combustion chamber. Such an arrangement is shown in Fig. 3a wherein the two axes of the ellipse formed by the atomiser orifices do not differ consider3 ably. In Pig. 3b a modified arrangement is shown wherein the oval is very flat.

I claim: 1. A fuel oil injection nozzle for insertion in an opening in the cylinder wall of an internal combustion engine, said nozzle including a body portion having an axially-extending bore through which the fuel passes on its way to the cylinder, a part of said body portion being within the opening in the cylinder wall and spaced from the 0 wall defining said opening to form an air space between said body portion and said wall and a part of said body portion extending outwardly beyond the cylinder wall, and a cap engaging said outwardly-extending portion and a portion secured to said cylinder wall to retain said body portion within said opening, said cap having openings through the top thereof, with air passages located between the air space surrounding that part of the body portion within the opening and the openings in said top to permit circulation of air through said air space, passages, and openings to effect cooling of said body portion.

2. A fuel oil injection nozzle as defined in claim 1 in which heat insulating material is applied to the outer surface of the body portion that is within the opening in the cylinder wall.

3. A fuel oil injection nozzle as defined in claim 1 in which the fuel passage through the body portion is lined with a conduit having its exterior surface provided with a coating of heat Insulating material in contact with the inner surface of the fuel passage.

4. A fuel oil injection nozzle for insertion in an opening in the cylinder wall of an internal combustion engine, said nozzle including a body portion having an axially-extending bore through which the fuel passes on its way to the cylinder, the inner end of said body portion having a plurality of atomizer orifices for injecting the fuel into the cylinder, a part of said body portion being within the opening in the cylinder wall and spaced from the wall defining said opening to form an air space between said body portion and said wall, and a part of said body portion extending outwardly beyond the cylinder wall and having a radially-extending lug thereon, and means for retaining said body portion within said opening, said means having passages extending therethrough and communicating with the air space surrounding said body portion to permit circulation of air through said passages and air space to effect cooling of said body portion, and said radially-extending lug being confined between the spaced walls of one of said passages to retain the atomizer orifices in fixed position with respect to the cylinder.

5. A fuel injection nozzle for insertion in an opening in the cylinder wall of an internal combustion engine, said nozzle including a body portion having an axially-extending bore through which the fuel passes on its way to the cylinder, the inner end of said body portion having a plurality of atomizer orifices for injecting the fuel into the cylinder, a part of said body portion being within the opening in the cylinder wall and spaced from the wail defining said opening to form an air space between said body portion and said wall, and a part of said body portion extending outwardly beyond the cylinder wall and having a radially-extending lug thereon, a sleeve secured to the cylinder wall and surrounding said outwardly-extending part of the body portion, said sleeve having a slot therein in communication with the air space surrounding said body portion and adapted to receive and retain the radially-extending lug on said body portion to maintain the atomizer orifices in fixed position with respect to the cylinder, and a cap engaging said outwardly-extending part of said body portion and the sleeve secured to said cylinder wall to retain the body portion within said opening, said cap having an opening through the top thereof in communication with the slot in the sleeve to permit circulation of air through said air space, slot and opening to effect cooling of said body portion.

6. A fuel injection nozzle for insertion in an opening in the cylinder wall of an internal combustion engine, said nozzle including a body portion having -an axially-extending fuel passage therethrough, a sleeve surrounding said body portion and spaced therefrom to provide an air space between said sleeve and body portion, said sleeve having openings therethrough communicating with said air space, and a cap secured to said sleeve and enclosing and engaging the upper end of the nozzle body portion for retaining said body portion in fixed position within said sleeve, said cap having an air passage therethrough communicating with the air space between said sleeve and body portion.

7. A fuel injection nozzle for insertion in an opening in the cylinder wall of an internal combustion engine said nozzle including a body portion having an axially-extending fuel passage therethrough terminating in a plurality of atomizer orifices, a sleeve surrounding said body portion and spaced therefrom to provide an air space between said sleeve and body portion, said sleeve having an opening therethrough communicating with said air space, and a cap engaging said sleeve and said body portion for retaining said body portion in fixed position within said. sleeve, said cap having an air passage therethrough communicating with the air space between said sleeve and body portion, whereby air may circulate through the opening in the sleeve, the air space between the sleeve and body portion and through the air passage through the cap.

8. A fuel injection nozzle for insertion in an opening in the cylinder wall of an internal combustion engine, said nozzle including a body portion having an axially-extending fuel passage therethrough terminating in a plurality of atomizer orifices and said body portion having a radially-extending lug thereon, a sleeve surrounding said body portion and spaced therefrom to provide an air space between said sleeve and body portion, said sleeve having an opening therethrough communicating with said air space and having a slot to receive and retain the radially-extending lug to prevent relative rotation between the sleeve and body portion, and means for securing the sleeve and body portion together, said means having a passage therethrough communicating with the air space between the sleeve and body portion whereby air may circulate through the opening in the sleeve, the air space between the sleeve and body portion and through said passage.

RUDOLF L'ORANGE.