US3263729A

US3263729A - Fuel ignitor arrangement for a heater

Info

Publication number: US3263729A
Application number: US386807A
Authority: US
Inventors: Fetter Zdenek; Musil Jaroslav; Kucera Miroslav; Pelikan Bohus; Leimer Jaroslav
Original assignee: VYZKUMNY USTAV PRISLUSENSTVI MOTOROVYCH VOZIDEL
Current assignee: VYZKUMNY USTAV PRISLUSENSTVI MOTOROVYCH VOZIDEL
Priority date: 1964-06-26
Filing date: 1964-06-26
Publication date: 1966-08-02
Anticipated expiration: 1983-08-02

Description

Aug. 2, 1966 z. FETTER ETAL FUEL IGNITOR ARRANGEMENT FOR A HEATER Filed June 26, 1964 M plu 1 F/GZ E a 71- E 2 ad w /f/A f77/(7.72%

United States Patent O 3,263,729 FUEL IGNITOR ARRANGEMENT FOR A HEATER Zdenk Fetter and Jaroslav Musil, Prague, Miroslav Kuera, Revnice, Bohus Pelikan, Jablonec nad Nisou, and Jaroslav Leitner, Zelezny Brod, Czechoslovakia, assignors to Vyzkumny us'tav prislusenstvi motorovych vozidel, Prague, Czechoslovakia Filed June 26, 1964, Ser. No. 386,807 7 Claims..l (Cl. 158-28) This invention relates to fuel-burning heaters of a type employed for heating motor cars, and more particularly to a fuel ignitor arrangement.

The heaters with which this invention is concerned are equipped with a heating chamber in which a combustible fluid, such as gasoline, is burned with air. To start combustion of the fuel, an electric spark is passed through a mixture of fuel and air. The spark may be energized by the ignition circuit of the car.

The object of the invention is the provision of an ignitor unit for a heater of the type described which is compact and eiiective, and whose working elements are readily available for inspection and repair, if needed, by removal of the ignitor unit from the combustion chamber.

Other objects and many of the attendant advantages of this invention will be readily apparent from the following description of preferred embodiments when considered in connection with the accompanying drawings in which:

FIG. 1 shows a rst embodiment of the invention in elevational axial section; and

FIGS. 2 to 4 respectively show additional ignitor units of the invention in views corresponding to that of FIG. 1.

Referring now to the drawing in detail, and initially to FIG. 1, there is seen a metal shell or plug 1 having an axial outer wall of stepped cylindrical shape. A hollow ceramic rod 3 is fixedly fastened in a bore of the plug 1 which passes axially through the same from one end of the plug 1 to an axially open cavity 9 in the other end and is offset laterally lfrom the axis of the plug. For the convenience of description, the end of the plug 1 formed with the cavity 9 will be referred to hereinafter as the lower end, and other spatial relationships will be described in an analogous manner. It will be appreciated, however, that the ignitor is operative in any position relative to the terrestrial field of gravity.

A wire electrode 2 enters the bore of the ceramic rod 3 at the top end and passes outward of the rod in a radial direction into the cavity 9. The free end of the electrode 2 in the cavity 9 is bent upward and tapered to a point.

Another axial bore of the metal plug 1 oiset from the axis in a direction opposite to the rod 3 -partly receives a nozzle assembly consisting of a supporting tube 4 and a nozzle 6. Threads 4 on the supporting tube 4 engage corresponding threads at the upper end of the bore in which the nozzle assembly is mounted. A shoulder 1 in the bore limits the threaded inward movement of the nozzle supporting tube 4. A portion of the axial passage 7 through the supporting tube 4 which .is above the metal plug 1 is provided with threads 5 for engagement with a corresponding fitting on a fuel pipe (not shown). The nozzle 6 is threadedly mounted on the lower end of the supporting tube 4 and projects into the cavity 9. It is axially aligned with the pointed free end of the electrode 2.

The lowermost portion of the plug 1 about the cavity 9 has radial openings 8 through which the cavity 9 may communicate with the ambient space.

The unit illustrated is inserted in a non-illustrated combustion chamber through a circular opening large enough to pass the lower half of the unit, but smaller 3,263,729 Patented August 2, 1966 rice in cross section than an integral external flange 1" on the plug 1. The liange 1" is seated on the combustion charnber in the normal operating condition of the unit, and is held there by a loose flange or other fastening means, not illustrated, which cooperate with the flange 1".

The nozzle 6 and the tube 4 consist of a metal, and are thereby grounded to the combustion chamber through the body 1 and the llange 1". A non-illustrated source of electrical potential energizes passage of a spark between the pointed end of the electrode 2 and the nozzle 6 which provides a counter-electrode when the two poles of the source are respectively connected to the electrode 2 and grounded in a manner not illustrated since it may be entirely conventional. The free end of the wire 2 above the ceramic rod 3 and the flange 1" thus constitute the electrical terminals of the unit.

When fuel is fed through the non-illustrated fuel pipe to the passage 7, and the circuit of the electrode 2 is simultaneously energized, the fuel discharged from the nozzle 6 in finely dispersed droplets is ignited by the spark.

The embodiments of the invention illustrated in FIGS. 2 to 5 operate in a manner closely similar to that of the unit shown in FIG. 1, and their operation will only be referred to as far as it differs from that described hereinabove.

The ignitor unit shown in FIG. 2 has a ceramic plug 11 which is almost identical in external appearance tov the plug 1. A wire electrode 12 is xedly fastened in the plug 11 and has a spark releasing pointed end in a cavity 19 of the plug which is open in an axial direction and communicates with radial openings 18 in the lowermost portion of the plug 11. A metallic bushing 13 is fixedly attached in the upper portion of an axial bore through the plug 11. Internal threads in the bushing 13 retain the supporting tube 14 of a nozzle assembly which also includes an atomizing nozzle 16 arranged opposite the pointed end of the electrode wire 12 for passage of a spark therebetween. A shoulder 17 on the tube 14 engages a radial annular end face of the bushing 13. The threaded engagement of the bushing 13 and of the tube 14 permits a grounding conductor (not shown) to be clamped between the tube and the bushing.

The ceramic body 31 of the ignitor unit shown in FIG. 3 has an integral projection 37 which extends downward into a cavity 30 between the ceramic body and a metallic ilanged sleeve 38. A wire electrode 32 passes axially through the body 31 and a major portion of the projection 37 which insulates the electrode and shields it against undesired electrical discharge toward the adjacent wall of the sleeve 38. The pointed straight terminal portion of the wire electrode 32 extends radially into the cavity 30 from the projection 37 and is aligned with a similarly pointed counter-electrode 39 which is attached to the sleeve 38.

Current passes from the wire electrode 32 in a spark through the cavity 30 to the counter-electrode 39, and thence to ground through the ange on the sleeve 38. The nozzle 36 is arranged to project a stream of ignitable fuel mixture into the spark, but is not itself an element of the electrical circuit, andV thereby protected from spark erosion.

Similar protection is afforded to the atomizing nozzle 46 of the ignitor unit shown in FIG. 4 which is otherwise very similar to the device shown in FIG. 1. Two axial bores in a metallic plug 41 of stepped cylindrical shape respectively receive axial portions of a hollow ceramic insulating rod 43 and of `a nozzle supporting tube 44 which projects upwardly from the plug 41 and is internally threaded in the projecting portion. The tube 44 is threadedly secured `in the plug 41 and a shoulder 47 limits threaded movement of the tube into the ybore 45 of the plug to the illustrated position in which the nozzle 46 supported on the lower end of the tube is recessed from the orifice 48 of the bore 45 in the axially open bottom cavity 40 of the body 41.

A wire electrode 42 passes axially downward through the insulating rod 43, then radially out of the rod into the cavity 40, and ultimately upward. The free end of the electrode 42 has a circular face 49 perpendicular to the direction of wire elongation. It is axially closely adjacent the orice 48 and centered with respect to the orifice so that a spark discharge from the electrode face 49 to ground takes place between the electrode and the body 41, not the nozzle 46.

Obviously, many modications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. An ignitor unit for a fuel-burning heating apparatus comprising, in combination:

(a) a shell having an axis and being formed with an axially open cavity and with two bores passing through said shell in the direction of said axis, said bores being offset from the axis in opposite transverse directions and having respective terminal orices axially communicating with said cavity;

(b) connecting means for connecting one of said bores with a source of fluid fuel;

(c) nozzle means in the orifice of said one bore for discharging a stream of said fuel into said cavity;

(d) an elongated conductor passing through the other bore, said conductor having an end portion in said cavity constituting an electrode and another end portion constituting a terminal;

(e) insulating means insulating said conductor from said nozzle means; and

(f) counter-electrode means mounted on said shell for passing a spark through the stream of fuel discharged from said nozzle means between said counter-electrode means and said electrode when an electric potential is applied to said counter-electrode means and said terminal.

2. An ignitor unit as set `forth in claim 1, wherein said counteraelectrode means include an electrode member arranged in said cavity spacedly adjacent said orifice.

3. An ignitor unit as set forth in claim 1, wherein said nozzle means constitutes said counter-electrode means.

4. An ignitor unit as set forth Iin claim 3, wherein said electrode is axially aligned with said nozzle means.

S. An ignitor unit as set forth in claim 1, wherein a portion of said shell adjacent said orifice constitutes said counter electrode means.

6. An ignitor unit as set forth in claim 1, wherein said shell is formed with `a plurality of radial passages therethrough communicating with said cavity.

7. An ignitor unit as set forth in claim 1, further comprising engagement means on said shell for fastening the unit to a combustion chamber.

References Cited by the Examiner UNITED STATES PATENTS 1,948,663 2/1934 Irvin 158-28 2,285,704 6/1942 Frank 158-28 FOREIGN PATENTS 242,674 7/1926 Great Britain. 621,789 4/ 1949 Great Britain.

d JAMES W. WESTHAVER, Primary Examiner;

Claims

1. AN IGNITOR UNIT FOR FUEL-BURNING HEATING APPARATUS COMPRISING, IN COMBINATION: (A) A SHELL HAVING AN AXIS AND BEING FORMED WITH AN AXIALLY OPEN CAVITY AND WITH TWO BORES PASSING THROUGH SAID SHELL IN THE DIRECTION OF SAID AXIS, SAID BORES BEING OFFSET FROM THE AXIS IN OPPOSITE TRANSVERSE DIRECTIONS AND HAVING RESPECTIVE TERMINAL ORIFICES AXIALLY COMMUNICATING WITH SAID CAVITY; (B) CONNECTING MEANS FOR CONNECTING ONE OF SAID BORES WITH A SOURCE OF FLUID FUEL; (C) NOZZLE MEANS IN THE ORIFICE OF SAID ONE BORE FOR DISCHARGING A STREAM OF SAID FUEL INTO SAID CAVITY; (D) AN ELONGATED CONDUCTOR PASSING THROUGH THE OTHER BORE, SAID CONDUCTOR HAVING AN END PORTION IN SAID CAVITY CONSTITUTING AN ELECTRODE AND ANOTHER END PORTION CONSTITUTING A TERMINAL; (E) INSULATING MEANS INSULATING SAID CONDUCTOR FROM SAID NOZZLE MEANS; AND (F) COUNTER-ELECTRODE MEANS MOUNTED ON SAID SHELL FOR PASSING A SPARK THROUGH THE STREAM OF FUEL DISCHARGED FROM SAID NOZZLE MEANS BETWEEN SAID COUNTER-ELECTRODE MEANS AND SAID ELECTRODE WHEN AN ELECTRIC POTENTIAL IS APPLIED TO SAID COUNTER-ELECTRODE MEANS AND SAID TERMINAL.