US2141787A - Igniter assembly - Google Patents

Description

IGNITER AS SEMBLY Filed Aug. 9,' 1937 MWENToRT Y HARM/v VERNE Ho/v/v.

BY 4 ATTORNEYS. l

Patented Dec. 27, 1938 UNITED STATES orties IGNITER ASSEMBLY Harlan Verne Honn, San Francisco, Calif.

Application August 9, 1937, Serial No. 158,130

9 Claims.

at predetermined temperatures and pressures; to

provide an igniter assembly which may be utilized to fire fuel charges of all types in an engine cylinder; to provide an igniter assembly wherein the amount, temperature and pressure of the exhaust gases may be accurately controlled; to provide an igniter having a controlled exhaust; and to provide a simple and eflicient method of producing controlled jets of burning fuel.

. Other objects of my invention will be apparent or will be specifically pointed out in the description forming a part of this specification, but I do not limit myself to the embodiment of the invention herein described, as various forms may be adopted within the scope of the claims.

This application is a continuation in part of my prior application, Serial No. 745,573, filed September 26, 1934, entitled Internal combustion engine, and is a continuation of my application, Serial No. 140,662, filed May 4, 1937, entitled Heavy fuel engine.

The two prior cases above-mentioned deal with the combination of an igniter assembly with a heavy fuel engine. The present application, however, is conned solely to the igniter assembly, as I have found that the igniter assembly is useful in firing any type of fuel charge, or is equally applicable to any use where a controlled burning exhaust may be usefully employed.

In the drawing, which is a duplicate of Figs. l and 2 of the later filed application listed above, and which differs from the prior filed application, supra, only in the method of supplying fuel to theigniter, Fig. l is a longitudinal sectional view of a portion of a cylinder head and igniter cylinder embodying my invention.

Figure 2 is a similar View showing another modification of utilizing a different fuel supply to the igniter cylinder.

In the following description it is to be distinctly understood that while I have shown and illustrated my invention as applied to a single air cooled cylinder, it is applicable to any type of engine having single or multiple cylinders, and it is also applicable to internal combustion engines operating with any of the known cycle relationships. For that reason I have not shown (Cl. 12S-143) connecting rods, crank shafts, cam shafts, or other appurtenances of the engine not related to the present invention, as such arrangements are well known to those skilled in the art.

It is also to be distinctly understood that in the present application I do not wish to be conlined in any manner to the combination of the igniter assembly with any particular type of engine cylinder, nor is it even necessary that the igniter be utilized in conjunction with an engine of any type. There are many other uses where a controlled flow of burning gases under high temperatures and high pressures may be desirable, and I have therefore shown the device as applied to an internal combustion engine purely 15 as an illustration of one such us-e, and as such I utilize the igniter to fire a heavy fuel charge in a Diesel engine.

My invention may be more fully understood by direct reference to the drawing.

In Figure 1 a cast cylinder head I is provided with air cooling ns 2 and preferably a hardened cylinder liner 3. The customary air intake and exhaust valves utilized for Dies-el operation of an internal combustion engine have not been shown, as there are many modifications of such devices and they are no part of the present invention. Bearing on the cylinder liner 3 is a piston provided with the usual rings 5, there being the usual combustion chamber t above the 30,

top of the piston.

The structure just described, comprisingl the head l, liner 3, and piston 4, will be termed hereafter the work cylinder. The piston d is connected to the crank shaft of the engine in the usual manner.

Inasmuch as I intend to describe my engine as operating with part of the fuel injected into the work cylinder, I provide the cylinder head l with a fuel injection nozzle supplied with fuel oil from a source at the proper time in the cycle through fuel pipe 9. 'The-cylinder head i is also provided with an exhaust conduit IE leading laterally through an igniter assembly attached to the side of the cylinder head. This igniter assembly comprises an igniter casting H carrying an igniter cylinder body l2 provided with an igniter cylinder liner i4. The igniter cylinder is much smaller than the work cylinder. In the igniter cylinder is a high pressure piston i5 reciprocated in the cylinder through the medium of a divided piston rod It joined by and adjusting nut assembly l1. The piston rod l@ terminates in a cam roller assembly i9, the cam roller bearing on a cam 20 driven in synchronism with the work cylinder piston dthrough the usual crank shaft and driving means.

Immediately above the igniter piston I5 is inserted a valve seat 2I, held down by a valve cage 22, the latter being screwed to the upper end of the cylinder liner I4. The valve cage carries a surge valve 24 operating in a valve sleeve 25, and forced against the seat 2l by valve spring 26. Valve 24 opens into exhaust conduit I0 and the valve seat 2l is provided with an ignition aperture 2l opening beneath the valve so that the contents of the igniter cylinder may be discharged into the exhaust conduit I0, and from thence into the work cylinder.

In the modification shown in Fig. 1, however, exhaust conduit I0 extends past the surge valve 24, and is continued as a fuel pressure channel 3G, making a one hundred eighty degree band, and opening into the igniter cylinder below the high point of the igniter piston travel as determined by cam 20. In the fuel pressure channel 30 I position a Venturi block 3I provided with an annular fuel channel 32 opening through multiple apertures 33 into the narrowest portion of the venturi thus formed. A fuel pipe 34 feeds the annular fuel channel 32.

Inasmuch as it is not important whether the igniter piston I5 is positively driven or roller driven, as shown, I may prefer to utilize an igniter piston return spring 35 bearing against the lower end of the cylinder liner through the medium of a cylinder spring retainer 36, and maintained in place by the usual spring retaining disc 3l.

I prefer to operate my engine on the fourstroke cycle system, and as one complete up-anddown stroke of the piston is a scavenging movement I prefer to start my operational descriptionY at the beginning of the charging stroke, after all scavenging has been completed. At some time after the firing stroke, (the time being at any portion of the complete cycle when no great pressure exists in the work cylinder chamber E, and therefore in the fuel channel 30), I deposit, by any convenient supply means, an ignition charge of fuel in the annular fuel channel 32 through igniter fuel supply pipe 34. It may be held there in any convenient manner, such as by a check valve in the fuel pipe. At the same time air is being admitted through the usual air intake valve into the work cylinder, and as the piston 4 starts to rise in the work cylinder the igniter piston I5 is dropping, due to the contour of cam 20. 'Ihe suction produced immediately closes the surge valve 24, and a slight negative pressure is produced in the igniter cylinder at the same time that pressure is being built up in the work cylinder. As soon as the descent of the igniter piston uncovers the closed end of fuel channel 3D there is a surge of air from the work cylinder through the fuel channel 30, and through the venturi, thereby withdrawing the ignition fuel in the annular channel 32 through apertures 33 into the fuel channel and thereafter into the igniter cylinder. The igniter piston then starts to rise faster than the work cylinder piston and to compress the fuel charge in the igniter cylinder against the surge valve 24. `I prefer to so adjust the tension of the igniter valve spring and the area of the surge valve face exposed to the work cylinder pressure with relation to the surge valve face exposed to the igniter cylinder pressure, that the igniter cylinder pressure may rise to a point where the igniter fuel charge is ignited by pressure. This pressure will vary, according to the type of oil used, from eighteen hundred to thirtyfive hundred pounds per square inch. After ignition the pressure will still rise until the pressure developed snaps open the surge valve, and the ignited charge will surge into the main combustion chamber. The work cylinder, in the meantime, has had the intake air compressed to a relatively low pressure, for example, to three hundred fifty pounds per square inch. At the same time, or slightly before the ignited charge reaches the work cylinder, I prefer to inject additional fuel through igniter nozzle l. Both the burning fuel and the injected fuel mix with the air, and iiame propagation is continued in the work cylinder, the ignition being accomplished by the burning injected fuel.

It is obvious that the ignition of the charge in the igniter cylinder and the subsequent surge valve opening can be timed to place the ignited fuel into the main combustion chamber at exactly the proper time to meet the auxiliary injected fuel for maximum effect on the work piston 4, usually arriving three or four degrees before the main piston starts down on the power stroke. At the proper time in the power stroke the exhaust valve opens and the main combustion chamber is scavenged on the next two strokes as is usual in this type of engine, and the power stroke is repeated.

In the modification shown in Fig. 2 the exhaust conduit I0 does not extend through into fuel channel 30, and I utilize a separate source of air entering above the Venturi block 3| through an auxiliary air pipe 40. Air may be supplied through this pipe under constant pressure inasmuch as no air will move through the fuel channel 3G except when the igniter piston is in its lowest position as shown in this figure. When the end of the fuel channel 3l) becomes uncovered aircan rush in carrying with it the fuel from the annular fuel ring in the Venturi block. After the piston rises air passage through the channel is automatically shut olf by the piston, and the ignition in the igniter cylinder proceeds, as described above.

It is obvious that if desired the entire charge may be injected into the work cylinder from the igniter piston,- and in this case I completely eliminate fuel injection nozzle 1. Both methods of operation are satisfactory, and in either case the operation of the igniter assembly is the same, the only difference being thelamount of fuel supplied to the annular ring 32 and the manner in which the device is throttled.

For example, when using an auxiliary injector nozzle 1 the amount of fuel supplied to the ignition venturi may be maintained constant, just sufficient to ignite the charge in the cylinder` chamber 6. If, however, no auxiliary fuel is supplied, then the charge deposited in the Venturi block must be varied in accordance with the power demand required from the main work cylinder. It is also possible to adjust the air passages and pressures in such a manner that when the complete charge passes through the igniter assembly very incomplete combustion is obtained therein, whereas if a firing charge only is desired, a more perfect combustion can be produced in the igniter cylinder.

Several features should be more fully explained with regard to the surge valve 24.l This valve is preferably provided with annular contact to the valve seat only adjacent the exhaust conduit I0 and the cylinder opening 2'I. Either the valve seat or the valve, or both, may be cut away to form an expansion chamber between these two annular rings, and when the valve rst cracks to let the burning charge out of the cylinder, this expansion chamber provides for an immediate snap of the valve to a wide open position. It is also to be noted that by changing the angle of the valve face and thereby changing the relative area of the top and bottom surfaces, the relative total pressures on the opposite faces of the valve may be changed, and those relative pressures, in conjunction with the setting of the spring 26, will determine when the valve shall open.

In actual operation 1 have observed that the valve remains closed until the predetermined pressure is reached and then snaps open with extreme speed, thus providing an immediate outlet for the burning gases. The gases do not tend to pass back through the fuel channel Sil because this channel is under a static pressure, due to the fact that the piston has closed the other end of this channel.

It is also to be noted that there is no head space in my preferred form of igniter, and that the piston completely occludes the cylinder cavity when at the top of the stroke. Furthermore, it will be noted that the piston is positively driven in such a manner that the explosive pressures caused by the burning of the gas do not tend to drive the igniter piston, but that the piston is moved steadily upward against the increasing pressure until the surge valve opens and the burning charge passes out, to be utilized for whatever purpose it is desired.

t should be pointed out also that in case the output of the igniter assembly is to be utilized for other purposes than the ignition of a burning charge in .an internal combustion engine, the relative pressures on the Valve and in the fuel channels may be provided by air pressure tanks or other auxiliary means, as may seem desirable within the knowledge of those skilled in the art.

It is to be distinctly understood that while my device operates to best advantage utilizing fuel oils of low grade which ignite readily by compression, that any fuel which can be controlled and ignited by compression may be utilized in the igniter cylinders. Furthermore, when the device is actually utilized in conjunction with an engine cylinder, the type of fuel utilized therein is of no importance whatsoever, except that it can be fired by these burning gases. The device, therefore, is useful in igniting fuels of any grade which are diflicult of ignition and where ilame propagation is slow cr difficult unless aided by an intimate mixture with a preignited material.

It is also to be fully understood that the gases emitted from my igniter assembly may be used directly, both as to their heat content and as to their expansive power, without being utilized to ignite an additional charge.

I claim:

l. in combination with a cylinder having a piston cooperating therewith to ignite a fuel charge by heat of compression, means for releasing the ignited charge .at a predetermined pressure comprising an exhaust conduit, a valve seat between said exhaust conduit and said cylinder, said seat having a relatively large opening into said exhaust conduit and a relatively small opening into said cylinder, a valve cooperating with said seat and having annular contact therewith at least adjacent both openings, a spring urging said valve against said seat, and means for building up a pressure in said exhaust conduit, the

relative areas of the valve surfaces exposed to the cylinder and to the exhaust conduit, and the spring pressure all being proportioned to hold the ignited charge until a predetermined pressure has been reached, whereupon the valve completely opens and discharges the burning gases into said conduit.

2. In combination with a cylinder having a piston cooperating therewith to ignite a fuel charge by heat of compression, means for releasing the ignited charge at a predetermined pressure comprising an exhaust conduit, a valve seat between said exhaust conduit and said cylinder, said seat having a relatively large opening into said exhaust conduit and a relatively small opening into said cylinder', a valve cooperating with said seat and having annular contact therewith at least `adjacent both openings, a spring urging said valve against said seat, means for building up a pressure in said exhaust conduit, the relative areas of the valve surfaces exposed to the cylinder and to the exhaust conduit, and the spring pressure all being proportioned to hold the ignited charge until a predetermined pressure has been reached, whereupon the valve completely opens and discharges -the burning gases into said conduit, and means for preventing said piston from moving in accordance with the pressure of said charge.

3. in combination with a cylinder having a piston cooperating therewith to ignite a fuel charge by heat of compression, means for releasing the ignited charge at a predetermined pressure comprising an exhaust conduit, a valve seat between said exhaust conduit and said cylinder, said seat having a relatively large opening into said exhaust conduit and a relatively small opening into said cylinder, a valve cooperating with seat and having annular contact there-` with at least adjacent both openings, a spring urging said valve against said seat, and means for building up a pressure in said exhaust conduit, the relative areas of the valve surfaces exposed to the cylinder and to the exhaust conduit, and the spring pressure all being proportioned to hold the ignited charge until a predetermined pressure has been reached, whereupon 'the valve completely opens and discharges the'burning gases into said conduit, the walls of said valve and seat being separated between their contacts to provide an expansion chamber.

4. In combination with a cylinder having a piston cooperating therewith to ignite a fuel charge by heat of compression, means for releasing the ignited charge at a predetermined pressure comprising an exhaust conduit, a valve seat between said exhaust conduit and said cylinder, said seat having a relatively large openlig into said exhaust conduit and a relatively small opening into said cylinder, a valve cooperating with said seat and having annular contact therewith at least adjacent both openings, a spring urging said valve against said seat, and means for building up a pressure in said exhaust conduit, the relative areas of the valve surfaces exposed to the cylinder and to the exhaust conduit, and the spring pressure all being proportioned to hold the ignited charge until a predetermined pressure has been reached, whereupon the valve completely opens and discharges the burning gases into said conduit, said piston and cylinder cooperating at the top of the piston stroke to eliminate head space completely.

5. in combination with a cylinder having a piston cooperating therewith to ignite a fuel charge by heat of compression, means for releasing the ignited charge at a predetermined pressure comprising an exhaust conduit, a valve seat between said exhaust conduit and said cylinder, said seat having a, relatively large opening into said exhaust conduit and a relatively small opening into said cylinder, a Valve cooperating with said seat and having annular contact therewith at least adjacent both openings, a spring urging said valve against said seat,

means for building up a pressure in said exleasing theg ignited charge at a predetermined pressure comprising an exhaust conduit, a valve 'seat between said exhaust conduit and said cylinder, said seat having a relatively large opening into said exhaust conduit and a relatively small opening into said cylinder, a valve cooperating with said seat and having annular contact therewith at least adjacent both openings, a spring urging said valve against said seat, means for building up a pressure in said exhaust conduit, the relative areas of the valve surfaces exposed to the cylinder and to the exhaust conduit, and the spring pressure all being proportioned to hold the ignited charge until a predetermined pressure has been reached, whereupon the valve completely opens and discharges the burning gases into said conduit, and means for utilizing exhaust conduit pressure for injecting fuel into said cylinder.

7. In combination with a cylinder having a piston cooperating therewith to ignite a fuel charge by heat of compression, means for releasing the ignited charge at a predetermined pressure comprising an exhaust conduit, a valve seat between said exhaust conduit and said cylinder, said seat having a relatively large opening into said exhaustrconduit and a relatively small opening into said cylinder, a valve cooperating with said seat and having annular contact therewith at least adjacent both openings, a spring urging said valve against said seat, means for building up a pressure in said exhaust conduit, the relative areas of the valve surfaces exposed to the cylinder and to the exhaust conduit, and the spring pressure all being proportioned to hold the ignited charge until a predetermined pressure has been reached, whereupon the valve completely opens and discharges the burning gases into said conduit, and means for utilizing exhaust conduit pressure for injecting fuel into said cylinder at the bottom of said piston stroke.

8. In combination with a cylinder having a piston cooperating therewith to ignite a fuel charge by heat of compression, means for releasing the ignited charge at a predetermined pressure comprising an exhaust conduit, a valve seat between said exhaust conduit and said cylinder, said seat having a relatively large opening into said exhaust conduit and a relatively small opening into said'cylinder, a valve cooperating with said seat and having annular contact therewith at least adjacent both openings, a spring urging said valve against said seat, means for building up a pressure in said exhaust conduit, the relative areas of the valve surfaces exposed to the cylinder and to the exhaust conduit, and the spring pressure all being proportioned to hold the ignited charge until a predetermined pressure has been reached, whereupon the valve completely opens and discharges the burning gases into said conduit, a fuel inlet conduit opening into. said cylinder and uncovered by said pistn at the bottom of the piston stroke, means for building up a pressure in said inlet conduit, and means for depositing liquid fuel in said inlet conduit prior to release of pressure therein by the uncovering of the cylinder opening by said piston.

9. In combination with a cylinder having a piston cooperating therewith to ignite a fuel charge by heat of compression, means for releasing the ignited charge at a predetermined pressure comprising an exhaust conduit, a valve seat between said exhaust conduit and said cylinder, said seat having a relatively large opening into said exhaust conduit and a relatively small opening into said cylinder, a valve cooperating with said seat and having annular contact therewith at least adjacent both openings, a spring urging said valve against said seat, means for building up a pressure in said exhaust Conduit,

the relative areas of the valve surfaces exposed to the cylinder and to the exhaust conduit, and the spring pressure all being proportioned to hold the ignited charge until a predetermined pressure has been reached, whereupon the valve completely opens. and discharges the burning gases into said conduit, a fuel inlet conduit opening into said cylinder and uncovered by said piston at the bottom of the piston stroke, a connection between said exhaust conduit and said inlet conduit, and means for depositing liquid fuel in said inlet conduit prior to release of pressure therein by the uncovering of the cylinder opening by said piston.

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