US2090366A - Motor ignition apparatus - Google Patents

Description

Aug. 17, 1937. R. M. SOMERS MOTOR IGNITION APPARATUS Filed April 1, 1936 2 Sheets-Sheet l xNvENToR c/aard M.

Sumers TTORNEY Aug. 17, 1937. R. M. SOMERS MOTOR IGNITION APPARATUS Filed April 1, 1956 2 Sheets-Sheet 2 m m R w s m vM d m m R ORNEY Patented Aug. 17, 1937 PATENT OFFICE MOTOR IGNITION APPARATUS Richard M. Somers, West Orange, N. J., assignor to Thomas A. Edison; Incorporated, West Orange, N. J., a corporation of New Jersey Application April 1, 1936, Serial No. 72,024

20 Claims.

This invention relates to ignition systems, and more particularly to systems of the type employed with internal combustion motors. The invention has particular reference to systems arranged for the production of igniting sparks which tempo rarily--e. g., for an interval at and after motor starting-are of extra intensity, and to the control means by which this extra spark intensity is provided.

The invention contemplates such control means in the form of a delay switch device for example of the thermostatic type-wherein the passage of current for an interval causes the throwing of the switch to alter (e. g., reduce) the spark intensity; by suitable connection of the switch device this interval is made dependent esesntially on the device parameters and adjustment. The delay switch device of course consumes some power for its initial operation, or

, throwing to spark-reducing position, and may be caused thereafter to remain in such position. by a continuing consumption of power. But I have found it in general unnecessary, and in certain respects positively undesirable, that the continuing power consumption be as great as the initial consumption; and an important feature of the instant invention resides in the automatic reduction of this power consumption at the time of throwing of the switch.

It is an object of my invention to provide means and arrangements for efl'ecting such automatic reduction. I

It is another object to provide improved means for producing extra spark intensity for an interval at and after motor starting.

Another object is the provision of dependable and long-lived delay switch means for controlling, the production of such extra spark intensity.

Another object is the provision of improved mutual arrangements of such a delay switch, its

actuating element, and the ignition system.

Another object is the provision of a thermostatic switch especially suited for use in the control of extra intensity spark production. A broad object is the provision of a generally improved ignition system.

Other and allied objects will more fully appear from the following description and the appended 50 claims.

In the description reference is had to the accompanying drawings, of which Figure 1 is a diagrammatic view illustrating a simple embodiment of my invention wherein the 55 spark intensity is altered by the appropriate exclusion and inclusion of series impedance from and in circuit.

Figure 2 is a like view illustrating a modified form of the embodiment of Figure 1;

Figure 3 is a like view illustrating an embodi- 5 ment wherein the spark intensity is altered by the appropriate inclusion and exclusion of a "booster" coil in and from circuit;

Figure 4 is a like view illustrating a more elaborate but otherwise generally similar embodiw ment;

Figures 4a and 4b are fractional views respectively illustrating the condition of the switch device of Figure 4 in different stages of operation; and

Figure 5 is a view similar to Figure 2 illustrating an elaboration upon the circuit of that figure.

The conventional portions of Figure l are first conveniently described. The numeral I designates a storage battery, such as is commonly employed in connection with the internal combustion motor of an automobile or other motor vehicle, with one of its terminals (for example the negative) grounded, as to the vehicle frame. The letter M designates an electric starting motor arranged to crank the internal combustion motor and having one terminal grounded; the openly biased switch S when closed connects the starting motor M with the battery I. The switch 2 is the ignition switch, which when closed connects the lead 5 with battery I; the lead 5 is then arranged to supply current to the ignition system, which comprises the coil or transformer 4 wound upon the core C, the condenser M, the current interrupter or circuit breaker 9, the distributor l9, and the spark plugs of the motor. The lead 5 is connected to one extremity of the primary 3 of the coil 4, the other extremity of which primary is connected through lead 7 with the breaker contact or point 8. The other breaker 40 point H is carried by the arm l0 and is oscillatorily moved into and out of contact with the point 8; it is connected by the lead l2 to ground. Across the points is shunted the condenser H.

In series with the coil primary 3 is connected the secondary l5, which in turn is connected through lead I"! to the distributor arm l8. Wires 20 connect the distributor with the high potential terminals of the individual spark plugs, one of which is shown as plug 2| having the gap 22 between its high-potential terminal and ground. The operation of this conventional portion is well understood and need not here be described further than to review the facts that the spark across the plug gap 22 is produced by the breaker 9 interrupting the flow of current through the primary 3-, and that the intensity of the spark is a function of the parameters of the coil 4, and of the rate of decay of current in the primary circuit ensuing the interruption.

In the arrangement of Figure 1 there is inserted an impedance, for example the resistance 38, in series with the ignition primary circuit, and the coil parameters are so established that 10 with this impedance in circuit there is produced a spark of normal intensity. There is provided in shunt to the impedance a switch (31) which ordinarily during motor operation is maintained open, thus then maintaining the impedance inl5 cluded in circuit and providing the spark of normal intensity. During starting and the initial motor operation interval, however, the switch 31 is closed to short the impedancei. e., to exclude on effectively disconnect the impedance from circuit'-and thus to provide increased primary current, correspondingly increased rate of decay thereof upon each interruption, and accordingly a spark of extra intensity. The illustrated resistance 38 (with switch 3'!) may be mechanically housed in a convenient container 6, and is electrically inserted in the lead 5, dividing the latter into portions 5" and 5' respectively on the battery and coil sides of the resistance. The thermostatic switch 31, which has been shown 30 shunted about the resistance 38 by leads 48 and' 49, includes an arm 42 (shown connected through lead 49 to the lead 5") carrying contact 44, and a bimetallic arm 4| (shown connected through lead 48 to the lead 5) carrying contact 43- both arms being for example mounted to an insulating block 45, and the arm 4| being biased or tensioned so that contact 43 tends to touch contact 44 but being heat-responsive to move contact 43 away from contact 44. A heating element 50 is closely associated with arm 4I-for example, wound about the latterso that upon its traversal by suflicient current for a sufficient time it will raise the temperature of the arm 4| sufficiently to throw-i. e., to open-the switch 31.

45 The closing of the ignition switch 2 is intended to supply current to the heating element and to start the heating thereofi. e., to initiate the interval at the expiration of which the switch 31 will open; upon this opening of the switch 31 the 50 resistance 38 is added to the system to reduce the primary current and thus the spark intensity. In order that the parameters and adjustment of switch 31 shall completely determine (except for the unavoidable influence of battery voltage) the length of the interval, the heating element 50 is connected between the 1ead5 and groundi. e., is in general in shunt or parallel relationship to the ignition system; this general arrangement or the heating element is shown and claimed in the co-pending applicationof Gwin C. Harris,

Serial No. 67,219, filed March 5, 1936. The connection of the heating element to ground is shown through the lead 5|; its connection to the lead 5, .however, may be efiected on either the battery 5 or ignition system side of the resistance 38-1. e., either to the lead portion 5" or to the portion 5'. According to the present invention it is made on the ignition system side, to the lead 5'; in Figure 1 it has been shown for example welded at the point 10 to the bimetallic arm 4|, which is connected to the lead 5'. With such a connection the resistance 38, when thrown into circuit by opening of the switch 31, is placed in series not only with the ignition system but also with the 7 heating element, and thus reduces the current through the latter as well as the former. Expressed in other words, the heating element is connected directly across the normal portion or the ignition system, so that when the voltage thereacross is cut down by the throwing into circuit of resistance 38, the voltage across the element is reduced. It will of course be understood that for similar effect on the ignition system the value of the resistance 38 will be established lower than in the case wherein the heating element current is never drawn through it. Purely by way of example there may be indicated as typical a choice or value for resistance 38 such that upon its inclusion in circuit it will cut the voltage across primary 3 (and heating element 50) from a normal battery voltage of some 6.3 volts to approximately 4.5 volts; this is a 30% voltage cut, and accordingly in the heating element 58 approximately a 50% cut in power dissipation.

A material such cut is very advantageous not only in the avoidance of unnecessary power waste, but also in the avoidance of continued overheating of the bimetallic arm 4|, etc.; this is of value in conserving the life of the switch device, and in maintaining it throughout motor operation at a temperature from which it can cool to ambient with reasonable rapidity for a normal successive operation of the system. All of this is of particular advantage when, as I prefer and have portant function of which is of course the suppression of arcing and disintegration at the contacts, of course has the effect or decreasing the heat losses from the switch portions-i. e., of improving their heat retentivity-so that under given conditions these portions tend to attain higher temperatures and to cool therefrom more slowly than in the case of unenclosed switch devices.

In certain cases the power dissipation reduction effected by the circuit of Figure 1 may be of a degree more than ideally necessary, and in almost any event it is permissible that it be of somewhat smaller degree. Advantage has been taken of this, in the modification of Figure 2, to eliminate the necessity for a separate resistance 38: in this figure a resistance 50a equivalent thereto is made a portion of the switch devicee. g., wound about the bimetallic arm 4| within the envelope 40 to form a portion of the total heating element. Thus the arm 42 may be provided with an L-shaped extension 42' to which there is terminally connected the resistance 50a, this being wound about the bimetallic arm 4| to an intermediate point 1| thereon, whereat it is welded thereto; from this point to the lead 5| the heating element 50 as in Figure 1 is provided. The electrical connection in circuit of the heating element portion 50a will be recognized as entirely similar to that of the resistance 38; and the manner of functioning of the modified circuit is quite similar to that of the circuit of Figure 1, excepting for the contribution of the element portion 50a to the continued heating or the bimetallic strip 4| after opening of the switch.

In view of the relatively low voltage dropping across this portion-typically some 1.8 voltsthis contribution is not a large one. The switch in Figure 2 is designated as 31' in view of the change from the switch of Figure 1.

The action of the circuit of Figure 2 in still effecting upon switch throwing a reduction in power dissipation in the total heating element (50 plus 50a) may be most readily apparent when it is noted that the switch 31 is shunted around the element portion 50a; thus so long as the switch remains closed the full batteryvoltage is impressed across only the remaining portion (50) of the element, whereas when the switch is opened the battery voltage is impressed across the total element, of course with reduced total power dissipation therein. Precise inverse proortion of the dissipations in the two cases to the resistance values of the portion 50 and the total 50--50a is of course upset by the passage of primary current through portion 50:: when the switch is open. but this factor does not upset the general relationships above mentioned.

The invention is not limited to employment with impedance arranged for serial insertion in the primary circuit, but may be employed with other arrangements for automatically altering the intensity of the spark. Thus in Figure 3 I have shown it incorporated in a circuit wherein the spark intensity is increased during the desired initial interval by the then inclusion in circuite. g., in parallel with the primary 3of a booster coil 6|. This is a coil wound upon an individual core C whichis without inductive relationship to the core C of the main coil; it appears to increase the rate of primary current decay upon each interruption, and hence the spark intensity, by strongly opposing any residual current flow in the primary 3 after the instant of interruption by the breaker 9-for both booster coil (so long as it is connected in circuit) and the primary 3 are in parallel and together form a closed circuit, and the residual currents produced in that circuit by the simultaneously collapsing fields of both coils tend to neutralize each other and so to produce the high rate of primary current decay. It will be understood that whereas in the circuits of Figures 1 and 2 the parameters of the main coil (4) are chosen to provide normal spark intensity with reduced voltage across the coil primary, they are chosen in the case of Figure 3 to provide normal spark intensity with full battery voltage across the coil primary (the booster coil 6| being assumed disconnected) accordingly the designating numerals for the main coil and its respective portions have been furnished in Figure 3 with prime marks.

In Figure 3 the lead 5 from ignition switch 2 to primary 3 is unbroken; and the booster coil (which may conveniently be included with the switch device in the container 6) is connected from lead 5 to the conductor 1 through the switch and lead 49, and through lead 64, thus being paralleled with the primary 3 when the switch is closed. The total heating element is connected from the lead 5 (e. g., from the extension 42' of arm 42, as in Figure 2) to ground; as inFigure 2 itmay comprise two serial portionsone (designated as 50c) being shunted across the switch by connection from extension 42' to the point 12 on the bimetallic arm 4|, and the other (designated as 59b) being connected from point 12 through lead 5| to ground. When the ignition switch 2 is first closed, the bimetallic arm 4| being at ambient temperature and the switch thus closed to parallel the booster coil 6| with the primary 3, the extra spark intensity is provided and the bimetallic arm 4| is subjected to heating by full battery voltage across the heating element portion 501;. After the interval required for sufficient heating of the arm, the switch opens, the impression of battery voltage is now across the total heating element SOD-50c to result in reduced total dissipation, and the booster coil is rendered substantially ineffective-not by complete open-circuiting thereof, but by the change of its connection from simple shunt across primary 3 to shunt across a serial portion only (501)) of a resistance (the total heating element) which in turn is connected across the primary. By choosing the parameters, as is readily done, so that the heating element portion 500 has a value of resistance which is substantial relative to the parallel impedance value of booster coil and winding portion 50b, there is readily insured a small continuing voltage drop across and current through the booster coil, and negligible effect therefrom, after opening of the switch. Preferably, though not necessarily, the value of resistance of 500 will be of the order of or greater than that of 50b. The switch in Figure 3 has been designated as 31" in view of the changes from earlier figures.

In Figure 4 I have illustrated an elaboration on the switch device of Figure 3, whereby the continuing current fiow through the booster coil may automatically be eliminated. The change of the switch device comprises the inclusion therein of a spring arm 39 interposed between and insulated from arms 4| and 42, and carrying contacts 39' and 39 adapted to touch respectively contacts 43 and 44. When the bimetallic arm 4| is cold and its extremity tends to press leftwardly as illustrated, all the contacts 43-39 and 39"-44 are connected together. The spring arm 39, however, is slightly rightwardly biased away from arm 42, so that as the bimetallic arm 4| inresponse to heating moves its extremity rightwardly the arm 39 first moves therewith, opening the switch portion 31a formed by contacts 39"44 to such a position as is illustrated in Figure 4a; continued movement of the bimetallic arm 4| is unaccompanied, however, by further movement of the arm 39, and therefore the auxiliary switch portion 31b formed by contacts 39'43 is thereupon also opened, as illustrated in Figure 4b. The connection of the two heating element portions which in Figure 3 were shown made to the point 12 on the bimetallic arm 4| are now made to the point 82 on the added spring arm 4|.

So long as the bimetallic arm is cold as in Figure 4 or has moved only to the position of Fig ure 4a., so that spring arm 39 remains connected thereto, the operation of the circuit will of course be identical with that of Figure 3, switch portion 31a acting as did the switch 31" of that figure and effecting upon opening a reduction of the total power dissipation in the device. Further arm movement to open the auxiliary switch portion 3Tb, however, breaks the connection of the intermediate heating element point 82 with the bimetallic arm 4| and the lead 48 and the booster coil 6|, completely open-circuiting the latter and effecting a further reduction of power dissipation in the switch device. Since the portion of the heating element connected to arm 42 and lead 49 is relieved by the auxiliary switch portion opening from carrying even a reduced booster coil current, it may if desired be of somewhat higher resistance value than the element portion-50c of Figure 3, and has accordingly been designated 5012; the switch portions 31a and 31b have together been designated as 31".

The use of an auxiliary switch portion to effect an automatic additional reduction of power dissipation in the switch device is of course not limited to the arrangements employing booster coils; thus the auxiliary switch portion may be employed in connection with the circuit either of Figure 1 01'' Figure 2, and in Figure 5 I have shown it employed in a circuit otherwise similar to that of Figure 2. In Figure 5 the external connections are those of Figure 2; but the switch device, ex-

cept for the heating winding, may be similar to that of Figure 4, the main and auxiliary switch portions having been designated respectively as 31a and 31b, and together as 31". The heating element, wound as before about the bimetallic arm 4|, may comprise serially the portion 50c terminally welded to the lead 5| and to a point 83 on the spring arm 39, the portion 50 terminally welded to the same point 83 and to a point 13 on the bimetallic arm 4|, and the portion 509 terminally welded to that point 1'3 and to the arm 42 extension 42.

So long as the bimetallic arm is cold or has moved sufficiently to open only the switch portion 31a, so that spring arm 39 remains connected thereto, the heating element portion 50 is of course short-circuited, and the operation of the circuit will be similar to that of Figure 2- winding portions 50c and 509 being respectively analogous to portions 50 and 50a ofthat figure,

and switch portion 31a acting as did switch 31 of that figure and effecting upon opening a reduction of the total power dissipation on the device. Further arm movement to open the auxiliary switch portion 31b, however, removes the short-circuit from the element portion 50f, adding this portion to the portion (50c) already shunted from lead 5 to ground and thus further reducing the power dissipation in the switch device.

. It will of course be appreciated that in the circuits of Figures 1 and 2 the heating element or portion forms a heating shunt across the ignition system, that such a shunt is formed in Figure 3 by the entire element 50b50c and in Fig- 50 me 4 by the entire element 50b50d. and that such a shunt is formed in Figure 5 by the element 1. In a motor system having a current source and an ignition system arranged for connection 65 thereacross to produce an igniting spark: means for altering the intensity of said spark; means in shunt relationship to said ignition system for controlling said altering means; and means responsive to said controlling means for altering the 7 0 power dissipation therein.

2. In a motor system having a current source and an ignition system arranged for connection thereacross to produce an igniting spark: control means in shunt relationship to said ignition sys- 75 tem; and means responsive to said control means for altering simultaneously the intensity of said spark and the power dissipation in said control means.

3. In a motor system having a current source and an ignition system arranged for connection 5 thereacross to produce an igniting spark: a heating shunt across said ignition system; and means responsive to heating of said shunt for reducing such insertion, said switch including a heating element connected in shunt to said ignition system and in series with said impedance upon insertion thereof. 20

5. In a motor system having a current source and an ignition system n ed for connectionthereacross to produce an igniting spark: an impedance adapted for insertion in series with said ignition system to alter the intensity of said 25 spark; and a thermostatic switch for effecting such insertion, said switch including a heating element having a portion connected in shunt to said ignition system, and an additional portion comprising said impedance. -30

6. In a motor system having a current source and an ignition system arranged for connection thereacross to produce an igniting spark; means, including a thermostatic switch, for altering the intensity of said spark; and a. heating element 35 forming a part of said switch, a portion of said element being in series with and a portion there of being in shunt to said ignition system.

7. In a motor system having a current source and an ignition system arranged for connection 40 thereacross to produce an igniting spark: means,

including a thermostatic switch, for altering the intensity of said spark; and a heating element forming a part of said switch, a portion only of said element being in series with said ignition 5 system.

8. In a motor system having a current source and an ignition system arranged for connection thereacross to produce an igniting spark: means, including a thermostatic switch, for alter- -50 ing the intensity of said spark; and a heating element forming a part of said switch, a portiononly of said element being in series with said ignition system, and said switch being connected across said portion.

9. In a motor system having a current source and an ignition system arranged for connection" thereacross to produce an igniting spark: heating means, comprising a plurality of serially connected portions, connected with said ignition 0 system; and means, including a switch thermally responsive to all of said portions,-for altering the intensity of said spark, said switch being connected across at least one but less than all of said portions.

10. In a motor system having a current source and an ignition system arranged for connection thereacross to produce an igniting spark: a heating shunt across said ignition system; and means responsive to heating of said shunt for both re- 'ducing the intensity of said spark and increasing the resistance of said shunt.

11. In a motor system having a current source and an ignition system arranged for connection thereacross to produce an igniting spark: means,

including a switch, for altering the intensity of said spark; and a heating shunt across said ignition system for controlling said switch, said switch being connected across a portion of said shunt.

12. In a motor system having a current source and an ignition system arranged for connection thereacross to produce an igniting spark: means connected with said ignition system for increasing the intensity of said spark; a heating shunt across said ignition system; and means responsive to heating of said shunt for both rendering said intensity increasing means at least substantially inoperative and decreasing the power dissipation in said shunt,

13. In a motor system having a current source and an ignition system arranged for connection thereacross to produce an igniting spark: means connected with said ignition system for increasing the intensity of said spark: heater winding means connected in shunt relationship to said ignition system; a thermostatic switch, responsive to said winding means, in series with both said winding and intensity increasing means; and resistance means shunted around said switch.

14. In a motor system having a current source and an ignition system arranged for connection thereacross to produce an igniting spark: means connected with said ignition system for increasing the intensity of said spark; heater winding means connected in shunt relationship to said ignition system; a thermostatic switch, responsive to said winding means, in series with both said winding and intensity increasing means; and additional heater winding means influencing and connected around said switch.

15. In a motor system having a current source and an ignition system arranged for connection thereacross to produce an igniting spark: a heat ing shunt across said ignition system; a closely biased switch connected across a portion only of said shunt and adapted to be opened by heating of said shunt; and means, in series with said switch and responsive to a closed condition thereof, for increasing the intensity of said spark.

16. In a motor system having a current source and an ignition system arranged for connection thercacross to produce an igniting spark: a heating shunt across said ignition system; closedly biased switch means connected across a portion only of said shunt and adapted to be opened by a predetermined heating of said shunt; closedly biased auxiliary switch means in series with said first switch means and adapted to be opened by further heating of said shunt; and means, in series with and responsive to closed conditions of both said switch means, for increasing the intensity of said spark.

17. In a motor system having a current source and an ignition system arranged for connection thereacross to produce an igniting spark: a heating shunt across said ignition system; means responsive to a predetermined heating of said shunt for reducing the intensity of said spark; and means responsive to progressive heating of said shunt for progressively reducing the power dissipation therein.

18. In a motor system having a current source and an ignition system arranged for connection thereacross to produce an igniting spark: control means in shunt relationship to said ignition system; means responsive to said control means for reducing the intensity of said spark; means operative simultaneously with said intensity reduction to reduce the power dissipation in said shunt;

and means operative after said intensity reduction for further reducing said dissipation.

19. In a motor ignition system: a thermostatic switch device comprising first and second contact means; a bimetallic arm carrying said second contact means and biased to close the same against said first contact means; and contactopening means comprising a heating element iniiuencing said bimetallic arm, terminally connected to said first contact means, and intermediately connected to said second contact means.

20. In a motor ignition system: a thermostatic switch device comprising openly biased first and second contact means; third contact means; a bimetallic arm carrying said third contact means and biased to close the same against said second, and said second against said first contact means; and contact-opening means comprising a heating element influencing said bimetallic arm, terminally connected to said first contact means, and intcrmediately connected to said contact means.

RICHARD M. SOMERS.

CERTIFICATE OF CORRECTION.

Patent No. 2,090,366.

August 957 RICHARD M SOMERS It is hereby certified that error appears in the printed specification of the'above numbered patent requiring correction as follows: Page 5, first column, line 19,1c1aim 15, after the word "spark" strike out the colon and 'insert instead a semicolon; and second column, line L7,. claim 20, before "contact" insert the word secondyand that the said. Letters Patent should be read with these corrections therein that the some may conform to the record of the case the Patent Office. 4

Signed and sealed this 12th day of October, A. D. 1957.

(Seal) Henry Van Arsdale.

Acting Commissioner of Patents.

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