US2322584A - Internal combustion engine control - Google Patents

Description

June 22, 1943. R. M. NARDONE 2,322,584

INTERNAL COMBUSTION ENGINE CONTROL Filed Oct. 51, 1940 28 lNSl/LA T/ON 4/ ,/2

INVENTOR. Ro/rreo M. Nara/one zmfi 42 4.

Mam 4 Patented June 22, 1943.

INTERNAL COMBUSTION ENGINE CONTROL Romeo M. Nardone, Westwood, N. 1., assignor to Bendix Aviation Corporation, South Bend, Ind, a cofporation of Delaware Application October 31, 1940, Serial ship. 363,781 6 Claims. (Cl. 123186)f w This invention relates to internal combustion engines, and particularly to the control of the ignition of fuel in the combustion chambers of such engines.

An object of the invention is to provide means for preventing premature ignition of fuel in any engine cylinder during the starting period, that is, the periodin which the engine is being rotated (cranked) by externally energized starting mechanism.

' With the commonly used low speed starting mechanism, the cranking speed oi tin-aircraft engine is too low to permit of sufiicient ignition current generation by engine-driven means; and as the main magneto, or magnetos, of the engine are engine-driven, it follows that they are not effective at these low cranking speeds. This deficiency is ordinarily compensated for by providing auxiliary ignition current producing means, operable during the startlngperiod, and not dependent upon rotational speeds for its effectiveness--an induction coil, for example. whose primary winding is fed by current from a storage battery,'and whose secondary winding connects with the main distributor, through which it delivers a shower of high tension sparks vat the several cylinder spark-plug gaps; but in order to guard against premature ignition the connection to the distributor is spaced from the main magneto connection by an amount that is suidcient to delay the spark until the piston has passed top dead center. whereas the main magneto connection results-when the speed becomes suiilcient to develop any spark at allin a spark occurrence slightly in advan e of arrival of the piston at top dead center.- While such advance firing of the fuel is desirable at normal running speeds, it is quite undesirable during the starting period, for at that period there is not sufllcient momentum to continue the piston on is upward course, and there will result a reverse rotation, or "back-fire of the engine.

.Such reverse rotation-may seriously damage the starting mechanism; and the present invention has for an object the elimination of the possibility of such an advance spark during the starting process.

A further object is to provide means for rendering an advance spark impossible during starting, said means being so constructed as to assure production, of such advance sparks as soon as the starting process is completed A further object is to provide means for inter locking the ignition circuitswith a. circuit leading the starting (cranking) mechanism,- whereby the timing of the ignition sparks is made to depend upon whether or not the starting mechanism is operating; the timing being shifted automatically when the starting mechanism operation is discontinued.

These and other objects of the "invention will become apparent from inspection of the following specification when read with reference to the accompanying drawing wherein is illustrated the preferred embodiment of the invention. It is to be expressly understood, however, that the drawing is for the purpose of illustration only. and is not designed as a definition of the limits of the invention, reference being had to the ap pended claims for this purpose.

In the drawing reference character 5 designates a switch housing of insulating material within which is an arm 8 rotatable on a spindle I at the center of the housing; the arm 6 being These contact elements are adapted to receive conducting wires connected as follows: contact i, a wire it, to the induction coil "-41, feeding the auxiliary rotating contacts i6 and i1 oi-the ignition current distributors It and 19, respectively; the latter being rotatable by gears or other parts driven from the engine crankshaft, as are also the main magnetos 2| and 22; the said wire 4| also leading to the terminal post 23 of the starter 24, whose associated terminal post 26 is the terminus of the return feed 21 leading back to the negative side of the battery 28; contact II, to the primary winding of main magneto 2|; and contact ID, to the primary winding of main magneto 22; the use of dual ignition" (two spark-plugs per cylinder) being assumed for the illustrated system, a1 though of course the invention is applicable to single or triple ignition as well.

As above indicated the contact arm 6 is insulated from the spindle 1, and such insulation is indicated at 3| in the drawing. This insulation 3| permits the segment I to complete circuits, by way of battery 28 and contact strip I, to the coil and starter 24.

The extension l2 of arm 6 likewise is provided with two electrically distinct conducting segments 4!) and 4| mounted on the extension l2, the latter being of insulating material. The spacing of the contact strips 40 and 4| is such as to cause them to have engagement at all times with the contacts H and I0, respectively, although in certain positions the engagement will involve the non-conducting ports 43, 44 and 45, the portion 43 being on the strip 40, and the portions 44 and 45 on the strip 4|. All conducting portions of the strips 40 and 4| are grounded as indicated and therefore the associated magneto primary windings are grounded whenever the contacts l and ||,o'r either of them, are registering with a conducting portion of the strips, 4|) and 4|; the grounded condition of the circuit being broken whenever from a conducting portion to a non-conducting portion.

In operation, the arm 6 is first rotated from the at rest" or dead position,,in which it is shown, and is caused to come to rest in the position designated position A on the drawing. In this position both the starter 24 and the auxiliary ignition circuit are energized, wherefore crankshaft rotation begins and igniting sparks occur in the several cylinders as the pistons therein passslightly beyond top dead center, on their successive power strokes-this delayed firing being due to the trailing position of contacts l6 and H, in relation to main magneto contacts 5| and 52, respectively, ofthe distributors. During this starting period the said contacts 5| and 52 are dead, due to the .grounded condition of the contact strips 40 and 4| on sector l2, said strips being then .in circuit with the main magneto primary windings.

When the engine fires and starts to run under its 'own power, the operator will move arm. 6 to position B, in which position both magnetos 2| and 22 will become operative simultaneously, due to the establishment of registry between the non-conducting portions 43 and 444 on the one-hand, and the contacts II and" I0, respectively, on .the other, therebyvinterrupting the grounded connections of the primary windings of the magnetos, and thereby enabling their conventional circuit breakers (shown at 49 and 50, respectively) to function and cause current to be periodically induced in the secondary windings which feed the distributor contact arms 5| and 52, respectively. If it is desired that this shift from the auxiliary ignition circuits to the main magneto circuits be of an over-lapping nature as a safety precaution against a temporary hiatus in ignition current supply, the spacing of the non-conducting portions 43 and as may be made to have such a relationship to the spacing of the auxiliary ignition segment 9 that registry will be effected between said portions it and 45 and the contact pins H and I0, respectively, just prior to the breaking off of registry between segment 8 of arm 6 and the terminal edge of the strip 9; but of course, it will be understood that when the angular swing of the arm definitely reaches position B there will, of course, be a complete interruption of current flow to the strips so that during the normal running of the engine, the ignition will be derived solely from the main magneto circuits, the distributor arms 5| and 52 of which will function to produce ignition in the several cylinders as the pistons therein successively approach top dead center on their respective comthe registry shifts pression strokes. Thus there will be effected an automatic advance of the ignition point as compared with that which prevails during the starting period when the auxiliary ignition circuits rather than the main magneto circuits were functioning.

When the engine is to be cut out, the arm 6 will be returned of course .to the dead position shown. Should it be desired to cut out one magneto, but not the other,'arrn 6 may be moved to position C or position D depending upon which magneto it is desired to cut out; such individual cutting out of magnetos being desirable on different occasions as, for example, to test the performanceof one as against the other. When the arm is moved to position C, the sparkplugs associated with magneto 22 will be cut out, for in this position contact pin ID will register with the grounded conducting portion 41 of the strip 4|, while the contact pin M will register with the non-conducting portion of the strip 40 and therefore the magneto 2| will continue to function. Conversely, in position D magneto 2| will cease to function due to the registry of pin H with grounded conducting portion 48 of strip 40; magneto 22, however,-now being effective by reason of the registry of pin II] with the nonconducting portion 45 of strip 4|. The terminal 23, 26 of the starting unit may be the terminals of an electric motor constituting the prime mover of such a unit, or they may be the terminals of any other electrical starter control, such as the firing electrodes of a powder igniting device, where combustible powder is the source of starting energy (as in my Patent No. 2,207,936, granted July 16, 1940).

The induction coil assembly BI is, of course, of conventional design and includes, in addition to the windings 46 and 41, the usual contacts 62 and condenser 63, all of which function in the usual manner (see Patent No. 1,214,555 to B. M. Leece).

What is claimed is:

The combination, with an internal combustion engine magneto, of engine starting means comprising a member for imparting initial rotary movement to the engine and an induction coil for facilitating ignition of fuel during operation of said member, and common means for controlling energization of both said starting means and said induction coil, said common means also acting to render said magneto ineffective so long as saidmember and induction coil remain energized.

2. The combination, with an internal combustion engine magneto and an advance-spark mechanism in circuit therewith, of engine starting means comprising a member for imparting initial rotary movement to the engine and an induction coil for facilitating ignition of fuel during operation of said member, and common means for controlling energization of both said starting means and said induction coil, said common means comprising a switch mechanism which also prevents energization of said magneto during the starting period, thus preventing premature passage of current to said advancespark mechanism, and consequent reverse rotation of the engine.

3. The combination, with an internal combustion engine, of separate starting and running ignition circuits therefor, a starting motor for facilitating starting of the engine, an energization circuit for said starting motor, and common means for preventing simultaneous energization of all said circuits.

4. The combination, with engine starting mechanism. of ignition circuits for said engine,

said circuits including a pair-of engine-driven current distributor elements and stationary con tact elements successively engaged thereby, but at different times corresponding to diiIerent points in the engines power cycle, and means for controlling said starting mechanism and ignition circuitsin such manner as'to prevent flow of ignition current to both said distributor elements simultaneously. I Y

5. The combination with engine starting mechanism, of ignitioncircuits for said engine, said circuits including a. pair of engine driven current distributor elements and stationary contact elements successively engaged thereby, but

at different times corresponding to different points in the engine's power cycle, and means for controlling said starting mechanism and ignition circuits in such manner as to cause the ignition current to flow, first, through one of said distributor elements and then through the other,

to vary the ignition timing in accordance with the setting of said controlling means, said lastnamed means including a switch mechanism which, in one position, causes energization of said starting mechanism and one ignition circuit, and in another position causes deenergization of said starting mechanism and said one ignition circuit, while simultaneously causing energization of another of said ignition circuits, wherein the timing differs from that of said first-named circuit.

6. The combination, with an internal combusa tion engine magneto, of enginestarting means comprising a member for imparting initial rotary movement to the engine and an induction coil for facilitating ignition of fuel during operation of said member, and common means for controlling energlzation of both said starting means and said induction coil, said common means comprising. a switch mechanism which also controls energization of said magneto, and said switch mechanism including a plurality of stationary contact segments and a single rotatable contact member 'e'ngageable selectively therewith, andmeans .for supporting said segments in such spaced relationship as to prevent simuitaneous energization of both said magneto and said induction coil.

ROMEO M. NARDONE.

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