US 2775234 A
Description (OCR text may contain errors)
Dec. 25, 1956 w. B. SMITS PACKING FOR INTERNAL COMBUSTION ENGINE Filed NOV. 25, 1953 United States Patent PACKlNG FOR INTERNAL COMBUSTION ENGINE Wytze Beye Smits, Voorburg, Netherlands, assignor to Smitsvonk N. V., Leidschendam, Netherlands, a research laboratory Application November 25, 1953, Serial No. 394,469
6 Claims. cl. 123-169) The invention relates to a packing for internal combustion engines. The packing, which usually has the form of a packing ring for one-cylinder engines or of a packing sheet for multi-cylinder engines,- generally consists of a sealing material, such as asbestos, mica, and the like, which may be reinforced by metal.
The invention has for its object to construct this packing in such a way that it may be used as a spark plug for the engine, so that the usual spark plug may be omitted. To achieve this object, the packing according to the invention has been designed as a low-voltage surface discharge spark plug, which is made to spark by means of condenser charges and/ or discharges.
The packing according to the invention may consist of two or more metal sheets between which is enclosed the sealing material, in which is embedded an electrode ring. When this sheet and the electrode ring are connected to the ignition condenser and the mass, sparks will pass between the sheets and the electrode ring, which sparks will creep along the sealing material. Since the available creeping distance is very large, viz. equal to the circumference of the cylinder, this spark plug will have a very long life, and will undoubtedly be able to function for a time exceeding the period after which the cylinder head has to be dismantled for the decarburation or repair of the cylinder; if necessary, during such repairs the packing may at the same time be renewed. Owing to the large size of the heat-delivering surface of this plug, it will be cooled very thoroughly, which is of great importance for the long life of the plug.
The spark plug may consist, for example, of a metal sheet, which is enclosed between two sheets of packing material, this aggregate again being enclosed between two metal sheets. Two creeping paths are then formed, and the sparks will always be generated in the place where the resistance of the creeping path is smallest.
With some engines it is desirable to generate more than one spark, e. g. two. In that case the spark plug may consist of two metal sheets separated by a packing sheet, said metal sheets being enclosed between two packing sheets, which in turn are enclosed again between two metal sheets. Near the creeping paths the outer sheets are bent about the creeping path. If some of this sheet material of one outer sheet is removed in a given place, and the same is done with the other outer sheet in a place diametrically opposite, no spark can be generated in these places, since the creeping path has become too large there. One may thus cause sparks to be generated simultaneously in the desired places. For this purpose the metal sheets may also be made noncontinuous, but in two sections shaped like sectors of a circle, each of these sections being connected to an ignition condenser.
When this packing comprising a spark plug is used, it
would no longer be necessary to provide the cylinder head with the usual opening for screwing on the spark plug. It is, however, desirable to keep this opening and .shut it oif with a plug, since the interior of a cylinder ice is usually inspected through this opening, and the highest position of the piston is thus determined for the setting of the ignition. Such an opening has the additional advantage that even if one of thespark plugs according to the invention should cut out, a conventional low-voltage surface discharge spark plug may be screwed into this opening, so that the cylinder in question can function again.
The invention is explained more in detail with reference to the drawing showing some embodiments.
Fig. 1 is a longitudinal cross-section through part of an engine cylinder with cylinder head.
Fig. 2 is a cross-sectionon the line H-II in Fig. 1.
Fig. 3 is a cross-section on the line III-III in Fig. 2, on a greatly enlarged scale, for a special embodiment.
Fig. 4 is a similar cross-section for another embodi ment.
Fig. 5 is a similar cross-section for a third embodiment.
Fig. 6 is a top view of a packing ring according to the invention for special purposes. r
In the drawing, the numeral 1 designates the cylinder of the engine in question, and 2 is the head of this cylinder. In the cylinder head there is an inlet or outlet valve 3. Between the cylinder 1 andthe cylinder head 2 has been provided a packing ring according to the invention. This ring consists of an annular sheath 4 of ductile material, e. g. copper, into which has been pressed heatresistant, electrically insulating material 5, e. g. asbestos, mica or the like. In this insulating material 5 is embedded an electrode ring 6. This ring is equipped with a protruding lip 7, to which an electric conductor for current supply may be connected. In the place where the lip 7 protrudes, the sheath 4 has a fairly large opening. Through this opening the insulating material 5 also protrudes. This construction prevents a spark passing, outside the cylinder space, from the lip 7 to the metal of the sheath 4 or to the engine parts 1 or 2.
The electrodes of the surface discharge spark plug are formed by the insides of the sheath 4 and the electrode ring 6.
The sparks will creep along the marginal surfaces of the insulating material 5 adjoining the cylinder space of the electrode ring 6 is periodically connected to the charged condenser 9 by means of a throw-over switch 8. This condenser is connected at one end to the throw-over switch 8, at the other end to the mass of the engine. By means of the throw-over switch 8 the condenser is connected alternately to a charging circuit 10 and to the electrode ring 6, 7.
For allowing the passage of the bolts by means of which the cylinder head 2 is secured to the cylinder 1, the electrode ring 6 is provided with wide openings 11 (Figs. 2 and 3). In the sheath 4 and the packing and insulating material are provided openings 12, 13, into which those bolts fit. Also in the places where the fastening bolts pass through the packing no sparking may thus take place. As appears from Fig. 3, the ends of the sheath 4 may be bent inwards at 9, so that two narrow creeping paths 7, 8 are formed. The annular electrode 6 may also have the shape of a T 10 at the inside (Fig. 4), so that creeping paths 19, 20 are formed.
The whole surface of the inside of the packing plug may serve as active surface of the spark plug.
Instead of a single electrode ring 6, two or more such rings may. be embedded in the insulating material.
An example of this is shown in Fig. 5, where 21 and 22 are two electrode rings with insulating material 5 lying in between, these sheets likewise being enclosed in insulating material 5, while the Whole aggregate is enclosed in a sheath 4 again. The inner ends of this sheath 4 are bent about the insulating material, so that creeping paths 15, 16 are formed. If in some places of the ends 17 and 3 18 of thesheath 4 some material is removed, sparks will no longer be-generated in those places, since these will always seek the path with the smallest resistance; thus one may eliminate some parts of the spark plug as active sparking surfaces: this is indeed of importance when the formation of sparks is to be avoided in certain places in the cylinder where sparks would have a detrimental :efiect on the'combusti'on. With this construction it is possible, for example, to generate two sparks simultaneously by connecting the annular electrodes 13 and 14 to two condensers, which supply their current simultaneously.
This is also possible with the embodiment according to Fig. 6. Here the annular electrode 6 is split into two sections Gaand 6b, which lie between the full insulat ing rings 5, and can be connected M19 and 20 to two ignition devices, which generate a spark simultaneously.
1. A combined head gasket and spark plug for an internal combustion engine comprising, insulating to semi-conductive material disposed between the head and block of 'said engine, and atleast' one electrode clamped in :said material and extending atleas't to the interior of a cylinder.
2. A head gasket according to claim 1 in which said material forms a surface to support a low tension surface discharge spark.
3. A head gasket according to claim 1, further comprising, two metal sheets sandwiching therebetween said material, the edges of said sheets adjacent said cylinder being bent toward each other while keeping free a path over said material for a surface discharge spark.
4. A head gasket according to claim 2 in which said electrode is T-shaped in cross section, the short legs of said T being located adjacent said cylinder and ending a short distance from said sheets to leave free said path.
5. A head gasket according to claim 1 in which said elect-rode comprises a plurality of sectors which are embedded in said material and insulated with respect to each other.
6. A head gasket according to claim 3 in which said g l l i 1