US2905775A - Ignition system for internal combustion engines - Google Patents

Description

J. DE RUG ERIS Sept. 22, 1959 IGNITION SYSTEM FOR INTERNAL COMBUSTION ENGINES Filed July 25, 1958 2 Sheets-Sheet l INVENTOR. John DeRugeris Sept. 22, 1959 J. DE RUGERIS IGNITION SYSTEM FOR INTERNAL COMBUSTION ENGINES 2 Sheets-Sheet 2 Filed July 25, 1958 INVENTOR John DeRugeris BY W United States Patent IGNITION SYSTEM FOR INTERNAL COMBUSTION ENGINES John De Rugeris, Campbell, Calif.

Application July 25, 1958, Serial No. 750,962 4 Claims. (Cl. 200-26) The present invention relates to the ignition system for the cylinders of internal combustion engines, such as are used in automobiles, air planes, motor boats, power stations and the like, to produce high voltage surges of electric currents which are sequentially applied to the spark plugs of these cylinders to cause ignition of the explosive mixture contained therein. More particularly the present invention relates to the devices, employed in such systems,

for producing the required current surges at the proper intervals.

1 'Devices of this kind comprise usually a step-up trans- :former which has a primary and a secondary winding,

and to said primary winding is applied a low voltage current from a suitable source of electric power, such as .a battery or a magneto.

This current is periodically interrupted at predetermined intervals to produce in the secondary winding accurately timed current surges of a higher voltage that are delivered in the proper order to .the cylinders of the motor or engine by a suitable current distributing means which operates in timed relation with the. engine shaft. To alternately interrupt and re-estab- -lish the current flow through the primary winding in prop- ..erly timed relation with the operation of the engine shaft, it hasbeen customary in the past to interpose a normally closed switch in the circuit of the primary winding, and said switch was opened and closed in quick succession to break and make the circuit, by rotary cam- .mingmeans mounted upon an auxiliary shaft that was .driven from the engine shaft in timed relation therewith.

. Ignition systems of this type have many serious disadvantages and defects. Due to the low voltage character of the supply current the make and break switches require very accurate adjustment of their cam-actuated contact points to assure proper operation. The useful life time of these points is limited because they become burnt and pitted by the sparks developed as they open and close. As a result, they must frequently be readjusted and/or replaced to maintain satisfactory perform- .ance of the engine, and both, adjustment and replacement of these points, require expert attendance. It has therefore been proposed more recently, to replace the camoperated make and break switches by a rotary switch arrangement comprising a stationary conductive brush in engagement with the peripheral edge of a rotary switch body which is mounted upon and turns with the auxiliary they come into contact with the stationary brush. Sys terns of this type do not have the problem of accurate adjustment of cam-actuated contact points. They are inherently more rugged and hence more dependable in oper ation and less in need for supervision and servicing by expert personnel than the systems employing cam-operated make and break switches. They have a much smaller problem of wear and have therefore a much longer period of useful life.

It is an object of my invention to provide an improved ignition arrangement of the latter type.'.

Another object of my invention is to provide an ignition arrangement, of the type referred to, that is of simple and rugged construction.

Still another object of my invention is to provide a rotary switch arrangement, for an ignition system, of the type referred to, that may readily be installed in conventional ignition systems in place of the cam-operated contact point switches.

An additional object of my invention is to provide an ignition arrangement, of the type referred to, that has no adjustment problem and no problem of wear, and which will give peak performance over practically unlimited periods of time. These and other objects of the present invention will be apparent from the following description of the accompanying drawing which illustrates certain preferred embodiments thereof and wherein:

Figure 1 is a fragmentary plan view of a distributor, for an automobile engine, wherein my invention is incorporated.

Figure 2 is a fragmentary perspective, partly in section, of some of the components illustrated in Figure 1.

Figure 3 is a plan view, similar to Figure 1, illustrating .a modified embodiment of the invention.

Figure 4 is a vertical section through the embodiment of the invention illustrated in Figure 3 taken along line '44 thereof; and

Figure 5 is a fragmentary perspective, partly in section, of yet another embodiment of the invention.

Having first reference to Figures 1 and 2, the reference numeral 10 indicates the outer case or housing of a distributor mechanism, such as is employed in automobiles, from which the dust cover has been removed. Rota-tably supported in said housing is the distributor shaft 12 which is driven from the engine shaft in timed relation thereto, in any suitable manner, such as by means of a belt and pulley train (not shown). Ordinarily the distributor shaft carries firmly secured to its upper end a sixor eight peaked cam structure depending upon the number of cylinders which the distributor serves, for opening with each revolution of the distributor shaft the conventional make and break switch six or eight times, as the case may be. In the embodiment of the invention illustrated in Figures 1 and 2, which represents a conversion of a conventional distributor in accordance with thepresent invention, both, the cam structure and the switch mechanism ordinarily associated therewith, have been removed and arranged co-axiallyaround the upper end of said shaft is an annular member 14 of an insulating material, such as Bakelite, which is rigidly supported from the internal frame structure 16 of the distributor in any suitable manner. 'Said annular member 14 is of a substantially larger internal diameter than the diameter of the distributor shaft, and rigidly secured to the inner face of said annular member is a ring member 18 of a hard, electrically conductive material, such as nickel steel. Provided in the upper edge of said ring member at points spaced equal angular distances apart are notches or recesses 20, and urged into electrically conductive contact with the upper edge of said ring member is the head 22 of a resilient arm 24 that pro jects radially from a centrally located cap 26. Said cap covers the end face of the distributor shaft 12 and is suitably secured to said shaft in conductive contact and for rotation therewith, such as by means of a headed screw 28 that passes through a central aperture in said cap and engages a threaded bore 30 which has been tapped into the shaft. The contact head 22 of arm 24 has the form of a short cross bar whose end edges are curved upwardly so that it presents a convex area 3-1 to the edge of the ring member 18, as shown in phantom lines in Figure 2. The arrangement is preferably such that the top surface 19 of the annular support member is flush with the top edge of the ring member and the contact head 22 is sufii- ..ciently long to bear partially against the top surface of the annular support member, so that it is supported by said annular member as it passes over the notches in the ring member during operation of the device.

In the particular embodiment of the invention illustrated in Figures 1 and 2, there are six notches or recesses 20 in the ring member 18 indicating that the device of the invention is to serve an engine having six cylinders. it will be understood that the number of notches may be less or more, depending on the number of cylinders in the engine, to which the device .of the invention is to be applied. The distributor shaft 12 is grounded through the housing in which it is rotatably mounted, as indicated at 32 in Figure 1, and a conductive lead member in the form of a screw bolt 45 passes from the inner face of the ring member 18 through said member and through the annular support member 14 to theouter face thereof whereat itforms a terminal 36. To said terminal is connected the low voltage end of the primary winding 38 of the induction transformer 40, as diagrammatically indicated in 'Figure 1, and said terminal 36 may also be connected by a lead 42 to the grounded condenser 44.

:In operation, when the distributor shaft 12 rotates, the head 22 of arm 24 glides along the upper edge of the ring member 18 and the top surface of the annular support member 14. When the head is in conductive contact with the ring member 18 by contact with the segments 46 of its upper edge intermediately of the notches .20, a circuit is established from the source of electric power 48, through the primary winding of transformer 40, the lead member 34, the ring member 18, the contact arm 24, cap 26 and the shaft 12 to ground 32. But whenever the head 22 passes over a notch 20, it remains supported by the annular member 14, but loses briefly conductive contact with the ring member 18, so that the above described circuit is momentarily interrupted. As a result thereof the primary winding 38 of transformer 40 induces a high voltage current surge of opposite polarity into the sec .ondary winding 50, which is delivered to the distributor diagrammatically represented by the ellipse 52 in Figure 1, and said distributor directs the current impulse in a well known manner to the proper spark plug in the cylinders of the engine (not shown); and as the contact head 22 passes over the notch and re-establishes contact with the consecutive edge 46 of the ring member, it re-establishes the initial current flow in the primary winding, which is effective upon interruption by the succeeding notch 20 in ring member .18 to deliver another current impulse of high voltage from the secondary winding 50 to the distributor 52.

The described attachment for converting the ignition system of an internal combustion engine in such a manner as to render the conventional cam-operated make and break switch with its numerous drawbacks and .dis advantages dispensable, is of extremely simple and inexpensive construction, and is easy to install in ignition systems of conventional design. It is highly effective and dependable in-operation and will perform for very long periods of use without break-downs and without need for adjustment or replacement of its component parts. There is no harmful wear because the head 22 is of a sturdy construction and the ring member may be made of a very hard metal, such as nickel steel. On the other hand, the sliding engagement of the contact headwith the upper edge of the ring member has a polishing effect which prevents the formation of deposits that may interfere With the proper operation of the device. Furthermore, due to the concave contact surface 31 of the head 22, the effective contact area between said head and the upper edge of the ring member 18 may be made very small, and as a result thereof the notches 20 may be made of a relatively small angular width, Without endangering their etfectiveness in breaking the primary circuit. Hence, many notches may be provided in a ring member of given "size. Alternatively, .the contact segments 46 of the ring member 18 may be made long in relation to the angular width of the notches 20 at the contact level, thus providing a relatively long period of time for a current build-up in theprimary circuit followed by .a suddenand brief interruption of said circuit, which is effective to induce an accurately timed current surge of maximum voltage into the secondary winding 50 for delivery in properly timed relation to the spark plugs of the engine cylinders.

The embodiment of the invention illustrated in Figures 3 and 4 comprises an annular support member 60 of insulating material, that surrounds the distributor shaft 62 coaxially and is suitably mounted upon the frame 6410f the distributor housing. Supported from and within said annular member are two coaxially disposed ring members 66 and 68 of a hard metal, which are spaced radially from each other. The circular'upper edges 70 and 72 of said ring members lie ina common horizontal plane. Provided in the upper edge 70 of the outer ring member '66 is a plurality of angularly equi-spaced recesses or notches 74 of narrow angular width, and provided in the upper edge 72 of the inner ring member 68 spaced the same angular intervals apart is an equal number of recesses or notches '76, the arrangement being such that the notches of one ring member are located on radii that bisect the angles defined by the radii which intersect the directly preceding and the directly succeeding notches in the other ring member. Hence all the notches or recesses provided in the described mechanism are in face spaced equal angular intervals apart from each other. Keyed to the upper end of the distributor shaft 62 is a cap 78 which maybe of insulating material, and suitably secured upon said cap are resilient arms 80a and 80b of an electrically conductive material, such as nickel steel. Said arms project radially from diametrically opposite points of the cap'118, and terminate in narrow contact fingers 82a and 82b, respectively, that extend over, and are of sufficient radial length to span, the upper edges 70 and 72 of both the ring members 66 and 68. The arms 80a and 80b are arched as shown at 83a and 83b, respectively, tourge the fingers 82a and 82b into conductive contact with the upper edges of *both said ring members. One of the ring members, such as ring member 66, is connected to the primary winding 84 of the induction transformer 85, as diagrammatically indicated in Figure 4, while the other-is connected to ground in any suitable manner, such as diagrammatically indicated at 86.

In practical operation, as the distributor shaft 62 turns and revolves the 'arms 80a and 80b with their fingers 82a and 82b held in contact with the upper edges of both the ring members and 68, the circuit through the primary winding 84 of the induction transformer is closed in that the contact fingers 82a and 82b establish 'a conductive connection from the outer to the inner ring member, which latter member is grounded as explained here inbefore and as indicated at 86. Such a situation is ;i1lu.s trated at A in Figure 3. However, when the contact fingers 82a and 82b encounter a notch 74 in the upper surface of the outer ring member 66, as illustrated in broken lines at B in Figure 3, the conductive connection between the two ring members is briefly interrupted, but the fingers 82a and 82b remain in contact with, and are .safely guided over the notch 74 by, the inner ringv member 68; and similarly, when the fingers 82a and 82b encounter a notch 76 in the inner ring member 68, as illustrated in broken lines at C in Figure 3, the conduc tive connection between the two ring members is briefly interrupted, but the fingers 82a and 82b remain in contact with the upper edge of the outer ring member 66. :In either case, the power circuit through the primary winding 84 of the transformer 85 is briefly interrupted. This is effective to induce a current surge of high voltage in the secondary winding 90, which current surge is delivered in properly timed relation to the distributor and from there to the proper spark plug in the engine with which the device is associated.

The embodiment of the invention illustrated in Figures 3 and 4 has the advantage that wear of the ring members 66 and 68 and of the contact fingers 82a and 82b is practically non-existent, and any wear that may occur after long periods of use, occurs uniformly, because the fingers 82a and 82b are always supported upon and by the ring members and never lose contact with one or the other, even when they encounter the current-interrupting recesses in the contact surfaces of said ring members. The contact fingers are therefore guided safety over these recesses and can never strike against the opposite corners or edges thereof, such as might wear them out in time and/or might wear off these opposite corners and in this manner increase unevenly the effective length of the current interruptions produced by said recesses. As an added advantage, the embodiment of the invention illustrated in Figures 3 and 4 makes it easy from a manufacturing point of view, to provide a device of given diameter with a very large number of circuit-interrupting recesses, such as is required in air plane engines comprising a large number of cylinders.

The embodiment of the invention illustrated in Figure 5 is similar to, and offers similar advantages as, the embodiment illustrated in Figures 3 and 4. It employs a pair of coaxially arranged ring members 94 and 96 of a hard metal that are insulated from each other and which are swept simultaneously by a common conductive brush 98. In the embodiment of the invention illus trated in Figure 5, however, said ring members are of equal diameter and are held coaxially around the upper end of the distributor shaft 100 in a superposed, axially spaced position. For this purpose they may be suitably secured to the inner face of an annular support member 102 of insulating material, which is mounted in the distributor casing. Provided in the inner surfaces 104 and 106 of said ring members equal angular intervals apart are recesses or notches 108 and 110 respectively, the arrangement being such that the row of recesses in each ring member is angularly displaced from the row of recesses in the other ring member by an angular distance equal to half the angular interval between the consecutive recesses in each of the ring members. One of the ring members, such as member 96 is grounded as indicated at 112, while the other is connected into the circuit of the primary winding of the induction transformer (not shown), as indicated by the lead member 114 which extends from the upper ring member 94 through the annular support member 102 to the outer surface thereof, where it forms a connector terminal 116. Mounted upon, and secured to, the distributor shaft 100 is a cap 118. Slidably held within said cap is a radially extending arm 120 that is urged outwardly by suitable spring means indicated at 121, and which carries upon its free end the hereinbefore mentioned brush 98. Either the arm 120 or the cap 118 or both are made of insulating material. The brush has the form of a vertically disposed cross bar of a hard conductive material, which is of sufficient length to extend over both the ring members, and it has a convex outer surface as shown at 99, that is urged into, and moves a sliding contact with, the inner surfaces of both said ring members whenever the distributor shaft 100 is in operation.

Ordinarily the brush 98 establishes a conductive connection between the two superposed ring members 94 and 96, but when it encounters a recess in one or the other of said ring members this conductive connection is momentarily interrupted, causing a high voltage current surge in the secondary winding that is associated with whatever primary winding is conductively connected to the ring member 94.

While I have explained my invention with the aid of certain preferred embodiments thereof, it will be under stood that the invention is not limited to the specific constructional details shown and described, which may be departed from without departing from the scope and spirit of the invention.

I claim:

I. In the distributor of an internal combustion engine, an arrangement for regulating the flow of electric power through the primary winding of the inductive transformer in the ignition system for the cylinders of the engine, said arrangement comprising a rotary shaft operable in synchronism with the engine shaft, a pair of ring members of electrically conductive material arranged coaxially around said shaft, said ring members having annular contact surfaces each containing an equal plurality of equi-spaced recesses, with the recesses in one of said annular surfaces located angularly midways between the recesses in the other one of said contact surfaces, a radially extending arm supported from said rotary shaft for rotation therewith, a conductive member supported from said arm in sliding conductive contact with both said annular contact surfaces, and means for connecting one of said ring members to ground and the other one of said ring members to the primary winding of the induction transformer.

2. In the distributor of an internal combustion engine, an arrangement for regulating the fiow of electric power through the primary winding of the induction transformer in the ignition system for the cylinders of the engine, said arrangement comprising a rotary shaft operable in synchronism with the engine shaft, an annular member of insulating material mounted coaxially around said rotary shaft, a pair of ring members of electrically conductive material supported from said annular member in positions coaxial with said shaft, said ring members having annular contact surfaces each containing a plurality of equi-spaced recesses, with the recesses in one of said annular surfaces located angularly midways between the recesses in the other one of said contact surfaces, a radially extending arm supported from said rotary shaft for rotation therewith, a conductive member supported from said arm in sliding conductive contact with both said annular contact surfaces, and means for connecting one of said ring members to ground and the other ring member to the primary winding of the induction transformer.

3. In the distributor of an internal combustion engine, an arrangement for controlling the current fiow through the primary winding of the ignition transformer, said arrangement comprising a rotary shaft, a pair of conductive ring members of different diameters supported coaxially around said shaft in such a manner as to be spaced radially from each other, said ring members having annular contact surfaces lying in a common plane and containing an equal plurality of angularly equispaced recesses, with the recesses of one located angularly between the recesses of the other, an arm supported from said shaft for rotation therewith, and a conductive member extending over both said annular contact surfaces and supported from said arm in conductive contact with both said surfaces.

4. In the distributor of an internal combustion engine, an arrangement for controlling the current flow through the primary winding of the induction transformer, said arrangement comprising a rotary shaft, a pair of superposed conductive ring members supported concentrically each ether in an axial direction, said ring memhers having vinternal contact surfaces of equal diameters containing an equalplurality of angularly equi-spaced 17elcesses, with .the recesses of one located angularly midways between the recesses of the other, and a conductive member supported from said shaft for-rotation therewith in conductive sliding contact with both said annular surfaces.

References Cited in the file of this patent UNITED STATES PATENTS Williams May 28', 1 940 Lindenblad :Sept.v 14, 1948 Wall Sept. 17, 1949 Klay July 24, 1 951 Stevenson Aug-.21, 1956

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