US1641421A

US1641421A - Ignition device

Info

Publication number: US1641421A
Application number: US45831A
Authority: US
Inventors: Louis O French
Original assignee: Individual
Current assignee: Individual
Priority date: 1925-07-24
Filing date: 1925-07-24
Publication date: 1927-09-06
Anticipated expiration: 1944-09-06

Description

1,641,421 Sept. 6, 1921 Q FRENCH IGNITION DEVICE Filed July 24, 1925 X9 I I /7 /2 H I l7 /0 23' v INVENTOR 6w; Q FWGIL I) bl Patented Sept. 6, 1927.

LOUIS 0. FRENCH, OF MILWAUKEE, WISCONSIN.

IGNITIODI DEVICE.

Application filed July 24, 1925. Serial No. 45,831.

The invention relates to ignition devices, and more particularly to igniters of the in candescent type.

lVhen liquid fuel issues from a spray nozzle, a relatively concentrated jet is formed along the axis of projection surrounded by a misty fringe of finely divided fuel particles, temporarily suspend-ed in the air around the main jet. One of the objects of this invention is to take advantage of this condition and arrange the electrically-heated incandescent element at the nozzle and outside of the main spray and in the region of the fuel mist given off by the spray as it issues from the nozzle, with the result that the main spray is not impeded in its fiow; the ignition of the fuel mist is readily effected by the wire, and its ignition will in turn ignite the main stream, as the ignition of this mistoccurs at the start of injection and through its flame propagation acts to convert the main spray into a stream of flaming fuel. Such a stream of burning fuel has decided advantages for starting purposes, or for use as a pilot ignition for another fuel charge, because the warming process is quickly effected, due to the heat furnished by the burning spray, and the fuel does not have a chance to coalesce or deposit itself upon the cold. or cooler walls of the chamber into which it is being sprayed, or upon other parts associated with the chamber.

As a further consequence of arranging thewire in the region of the mist and outside the main jet, I find that the heat necessary to ignite the mist is less than that required where the main spray, or apart of it, is directed against the wire, with the result that av relatively short wire may be used, which has the advantage of reducing the amount of current necessary for ignition, and reducing the liability of the wire burning out quickly under high temperatures encountered in the engine, since with a short wire the relative rate of conductivity to the cooler terminals will serve to keepthe temperature of the wire from becoming excessive.

This application is a continuation in part of an application for ignition devices filed by me ,on March'25, 192, Serial No. 18,206. and an application for ignition devices filed by me on June 5, 1925, Serial No. 35,119,

as to common claimable subject-matter. In these prior appllcations the fuel conduit was insulated from the main body of the casing,

element;

and while this had certain advantages, it had the disadvantage of necessitating a packed and insulated oint for the fuel supply pipe, or a conduit section of insulating material in the fuel line. I find that a packed and insulated joint in the fuel line complicates the construction and increases its cost, and is liable to leakage, and I find that a conduit section of insulating material is liable to crack or rupture under the fuel pressures commonly used, and that it is difficult to make and maintain tight pipe connections therewith. To overcome these difficulties, I provide an insulated terminal for one end of the hot wire, independent of the fuel conduit, and ground the other end of the wire in any suitable manner.

As in the aforementioned application, Serial No. 35,119, I provide a hot surface member associated with the jet in the same manner as the hot wire, which will perform the functions of the hot wire after the engine has become heated and the current to the wire is cut ofi. p

The invention further consists in the several features hereinafter set forth and more particularly defined byv claims at the conclusion hereof.

In the drawings: Fig. 1 is a vertical sectional view through an igniter embodying the invention, taken along the line 11 of Fig. 2; p

Fig. 2 is a bottom end View of the igniter shown in Fig. 1, with the hot surface'elem-ent removed;

Fig. 3 is a side view. of the hot surface Fig. '4: is a vertical sectional view of a modified form of the device;

Fig. 5 is a detail view of an incandescent element before securing it to the ignitor.

Referring to Figs. 1 moral 6 designates a plug casing having threaded engagement with the cooled engine cylinder or head 6, 7 a terminal member, and 8 an exposed, ance element or wire. 7 I

The terminal member 7 is inthe form of a bolt which ismounted in but'insulated from the casing 6 by a micasleeve 9 and a metal washer-'12 which has a terminal exto 3, and 5, the nuelectrically-heated resisttension 13; provided with a supply wire binding screw 14.

The head 7 of the bolt 7 has a transverse opening to receive one end of the element 8 which is clamped therein by a screw 15 in threaded engagement with the head and extending at right angles to and into contact with the wire. The other end of the wire is grounded on and secured to the casing 6 by a screw 16 in threaded engagement with the lower end of the casing from which heat is conducted to the cooled head or cylinder 6 of the engine.

A fuel injector is secured to or formed integral with the casing 6. As shown, the injector is formed in the casing by a conduit 17 and a spray nozzle or discharge opening 18.

To control the supply of fuel to the engine, any suitable valve may be associated with the spray nozzle, and in the present instance I have shown a check valve fitting 19 secured to the casing and having a check valve 20 held closed by a spring 21 and opened by fuel pressure.

The incandescent element, connected, as above described, immediately in front of the nozzle 18, is in the form of a coil surrounding but disposed outside of the main path of the fuel jet issuing from the nozzle 18 and in the region of the mist or outer fringe of the spray. With a wire of relatively heavy gauge, such as No. 16 B. d: S, a single plain coil may be used but with wires of smaller gauge, such as 19 B. & 8., or smaller, I find that better ignition is produced by forming the wire as shown in Fig. 5, that is, into a. looped or corrugated form with the sides 22 of the corrugations or loops extending substantially parallel with the axis of the main jet. IVith such an arrangement the wire 8 does not interfere with the flow of the jet,

and the mist of finely divided fuel particles given off as the fuel issues from the nozzle and which are temporarily suspended in the air around the jet are quickly ignited by the wire, and I find that this ignition takes place as soon as the fuel starts to flow from the nozzle 18 and that the flame thus produced acts to ignite the main stream of fuel as it flows from the nozzle, with the result that the spray is converted into a stream of flaming fuel. This would not happen if the jet or heavy spatter from the jet were directed against the wire, as is the general practice, because under such conditions the wire is cooled rapidly and ignition is retarded and when it does take place is localized and by that time much of the spray has been deposited upon the cold or relatively cool walls of the engine. However, where the liquid fuel is converted into a flaming stream the warming process is quickly effected, due to the greater heat furnished, and the chance of the fuel coalescing and depositing itself upon the cold or cooler walls of the chamber into which it is being sprayed are minimized.

In some engines the temperature conditions are not such as to cause continued automatic ignition after the engine is started, but are such. as to furnish heat to a hot surface which will cause ignition, and I have associated a hot surface member 23 with the injector and hot wire in such a manner as to have said member assume the function of igniting the fuel after the current to the wire is cut off. In Figs. 1 and 3 this member is shown in the form of a sleeve or tube having one end adapted to fit over the reduced end 23 of the casing and having a body part 24 heat-insulated from said end by a plurality of slots or holes 25 and with its lower part 26 converging inwardly to a central opening 27 alined with the axis of the fuel jet. The size of the opening 27 is such that its edges or the adjacent walls 26 are not et1mp1ng1ng surfaces but are disposed outside of the main path of the fuel 7 jet and in the region of the mist or outer fringe of the spray, with the result that as the lower end of said member becomes highly heated, during the running of the engine, the mist of finely divided fuel particles temporarily suspended in the air around the jet are ignited by this member and serve just as explained in connection with the wire to convert the spray into a flaming stream so that ignition of the charge follows its injection into the engine, and, the main body of said member 23 is kept hot its heat-insulating connection with the casing 4. r

In the form shown in Fig. 1 the fuel injector is shown as separate from the ignitor casing 29, which is here shown as a'conduit or coupling having a threaded connection 30 at one end, with the cooled cylinder or head 30 of the engine and a threaded opening 31' at the other end to take the injector-plug or casing 32. This casing 32 has a. fuel conduit 34 with a check valve fitting 35, similar to the check valve 19 shown in detail in Fig. 1, at one end, and a removable nozzle member 86 having the spray opening 37 therein. The incandescent element 38 is here shown in the form of a single coil arranged withreference to the opening 37 in the same way as the element 8. One end of this coil is grounded to the shell 29 by aclamping screw 39, while the other end is mounted in the head of a bolt 40 and secured'thercto by a screw 41. The bolt 40 extends through an opening in the side wall of the casing 29 and is suitably insulated therefrom by mica washers 42 and a mica sleeve'43, and is clamped thereto in the same manner as the bolt 7 by a nut 44. A current supply wire binding nut 45 is mounted on the threaded end of said bolt. A hot surface member 46 in the form of a flanged ring has a tight fit in the bore 47 of the casing 29 With a central opening 48 and slots 4:9 to heat-insulate the ring portion from its securing flange, the size of the opening 48 being related to the fuel nozzle 37 in the same Way as the opening 27 related to the nozzle 18.

In. either" case current from a battery or other suitable source of supply is conducted to the insulated terminal member or electrode and passes through the Wire to the plug casing connected With the engine Which has a ground circuit to the current source.

The ignitor With the resistance element alone may be used as a starting ignition device for injection type internal combustion engines in Which the heat of compression is insufficient to start the engine from cold, the current to the Wire being cut off after the engine has become Warm, or it may be used as a pilot ignition device whereby the flaming spray is used to ignite another charge of heavier fuel Where the engine Works on low or medium compression pressures, in Which case the current to the Wire may be supplied intermittently. Furthermore, Where the compression or heat developed in the engine is insufficient to continue subsequent ignitions. under varying loads, during running, With the current to the Wire shut off, I haveprovided a hot surface member to effect ignition. In both instances the main flow of the fuel jet into the combustion chamber of the engine is not interfered With and the Wire and hot surface member are so disposed as to most readily effect the ignition of the fuel charge, and in the case of the Wire at relatively small expenditure of electrical energy and under conditions preventing rapid deterioration of the Wire.

I desire it to be understood that this invention is not to be limited to any particular form or arrangement of parts except in so far as such limitations are included in of an exposed electrically-heated coiled ignition Wire arranged adjacent the discharge nozzle of the ln ector and through Which the main spray has an unobstructed path as 1t issues from said nozzle, said Wire being disposed in the region of the fuel mist given off by the fuel on its issuance from the nozzle.

3. The combination With a fuel injector, of an exposed electrically-heated coiled ignition Wire arranged adjacent the discharge nozzle of the injector and through which the main spray passes directly after leaving the nozzle, said Wire being disposed in the region of the fuel mist given off by the fuel on its issuance from the nozzle and having looped portions extending substantially parallel With the axis of the nozzle.

4. The combination of a casing provided with a fuel conduit and spray nozzle, a fuel control valve associated With said conduit, an electrode distinct from said nozzle and mounted in said casing and insulated therefrom, an electrically-heated resistance element disposed in the region of the fuel mist given off by the fuel on its issuance from said nozzle, arranged in close proximity to said nozzle and past Which the main spray has an unobstructed path as it issues from said nozzle, said element having one end secured to said electrode and the other end secured to said casing.

5. The combination with a fuel injector, of an electrically-heated resistance element arranged adjacent the discharge end of the injector and outside of the main spray and in the region of the fuel mist surrounding the main spray, and a hot surface ignition member past Which the main spray passes unobstructively and arranged at the discharge end of the injector and outside of the main spray and in the region of the fuel mist surrounding the spray.

6. The combination With a fuel injector having a casing, of'an electrically-heated resistance element arranged adjacent the discharge end of the injector, and a member secured to the casing and having a heat-insulated hot surface portion disposed adjacent the discharge end of the injector and spaced from the main path of the spray.

7. An ignition device for injection type internal combustion engines, comprising a casing having means connecting the fuel injector With the combustion chamber of the engine, and an electrically-heated resistance element associated with said casing and arranged to ignite fuel mist as it formsat the discharge end of the injector about the main spray as the fuel charge issues from the injector. I

In testimony whereof, I affix my signature.

LOUIS O. FRENCH.