US2107266A - Ignition control apparatus - Google Patents

Description

Feb. s, 1938. J, L, ARTHUR 2,107,266

IGNITION CONTROL APPARATUS Filed May 3, 191 54 2 Sheets-Sheet 1 RETARD ADVANCE a! 20 a: 62 f2? 28 2 I6 .72 go 24 .30

'T Z? 7K w' -25 6 23 u l .7; J 22 73 72 INVENTOR 2/ JameaL.dr//ur ATTORNEYS Feb. 8, 1938.

J. L. ARTHUR 2,107,266

IGNITION CONTROL APPARATUS Filed May 3, 1934 2 Sheets-Sheet 2 ATTORN Patented Feb. 8, 1938 UNITED STATES PATENT OFFICE 2,17356 IGNITION CONTROL APPARATUS Application May 3, 1934, Serial No. 723,643

4 Claim.

This invention relates to ignition timers for internal combustion engines and more particu larly to a timer-distributor unit having a circuit interrupter, and a shaft driving the interrupter and means for altering the angular relation of the interrupter and driving means in accordance with engine load conditions.

One of the objects of the present invention is to simplify the construction, as well as provide controlling means for ignition timers, that is automatically actuated, either directly or indirectly by the engine for advancing and retarding the spark in accordance with the power curve of the engine.

One manner of securing the above objects is to provide an ignition system, wherein an engine suction operated device, which is automatically operable in accordance with the load upon the engine, is associated with devices which include means adapted to effect the advancing and retarding of sparking impulses in the ignition circuit diflerent degrees, upon equal increments of movement of the suction operated device.

These devices which include the means for effecting this variation in the advancing and retarding of the sparking impulses in the ignition circuit, are so constructed that the degree of variation in the advancing and retarding of the sparking impulses is directly in accordance with the load condition upon the engine, so that the ignitionmay be supplied to the engine at such times ,as may be found to be most advantageous, in accordance with the load under which the engine is running, and also in accordance with the power curve of the engine.

A further object of the invention is to provide suitable mechanical connections for ignition timers and their controlling devices that the spark timing control may be caused to follow the power curve of a particular type of engine as closely as possible in the advancing and retarding of the time of occurrence of the sparking impulses. This is accomplished by the use of super-imposed brackets mounted upon the shank oi the distributor, one of which is pivotally mounted on the timer unit andsupports the suction operated control means, while another bracket is rigidly mounted on the timer unit and provides for an articulated connection between the rigid bracket and a movable element of the control unit. That articulated connection includes cam means cooperating with a cam-follower, and connected by smmbre means to the movable element of the suction device. 1

A further object is to produce an efficient and economical mechanical coupling for diaphragm movement in suction automatic distributors.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 is a view embodying the present invention showing the suction means in section, and its connection to the timer, with the distributor cap of the latter removed.

Fig. 1A is a sectional view taken on line- |A--IA of Fig. l, and illustrates the hold-down means for the unit. 7

Fig. 2 is a view partly in section and partly in elevation taken substantially on line 22 of Fig. 1.

Fig. 3 is a fragmentary sectional view taken on line 3-3 of Fig. 2 further illustrating the cam and follower relation.

Fig. 4 is a view similar to Fig. 1, showing a modified form of the present invention.

Fig. 5 is a view partly in section and partly in elevation taken substantially on line 5-5 of Fig. 4.

Fig. 6 is a detail view in section, substantially as indicated by the line and arrows 5--6 of Fig. 4.

It is well known in the engine art, particularly of the combustion and explosion type, that engines of diiferent makes have different power characteristics. That is, what is known as the power curve of the engine, is afiected by a great many different conditions, such as dimensions of the fuel intake and exhaust manifolds, the area in the combustion chamber, piston displacement, engine produced fluid pressures within the fuel pipe and chambers, and many others.

Due to these various conditions which are present in different makes and types of engines, it has been found that the time of occurrence of the sparking impulses during operation under different engine loads, should vary substantially in accordance with the power curve of the particular type of engine to which the ignition system is to be applied. That is, in certain types of engines, a much greater degree of advance of the sparking impulses will be required to give a corresponding equal efiiciency from a power stand-point than will be required for certain other types of engine.

In the coupled relation of the engine or power plant to the road wheels of the vehicle, the power curve then will be somewhat analogous to the load conditions of engine operation, and the control effected by the engine produced suction device will be in part at least a control in accordance with the engine load conditions.

In the present improvements, the power curve of the engine is first ascertained by suitable dynamometer or other appropriate tests by which data is obtained showing the setting of the timer which is required in order that the engine will give the maximum of power at a given load. The curve of maximum power, showing the setting of the timer corresponding to the load is plotted on coordinate paper from the data obtained, and this power curve is used so as to enable the mechanism, which will be described hereinafter, to be constructed in accordance with the requirements of the particular type of engine in order that the maximum power may be produced for any given load.

This mechanism is combined with an engine suction operated device, which is controlled by the load of the engine, and this suction device will tend to actuate the aforesaid mechanism in such a manner as to provide ignition at the time it will accomplish the most effective combustion of the engine charge, both in accordance with the load of the engine, and the power curve of the engine.

The ignition timer-distributor comprises a housing 20 provided with a shank 2| received Within an opening 22 of the engine base 23. The shank 2| provides a bearing for a shaft 24 that carries a gear meshing with a gear driven by the engine, both of which are not shown. The shaft 24 drives a weight supporting plate 25 carrying the pivot pins 26 that pivotally support weights 21. The pins 26 are connected by springs 28 with pins 29 carried by an arm 30. The arm 30 is fixed to a cam shaft 3| pivoted on a reduced extension of the shaft 24, and has cam faces engaging extensions of the weights 21. The springs thus tend to move the weights 2"! inwardly toward the cam shaft or sleeve 3| mounted on the upper portion of the shaft 24.

The housing 20 supports an interrupter plate 32 carrying a pivot stud 33 upon which a circuit breaker lever 34 is pivoted. The interrupter plate 32 carries a stationary contact 35 that cooperates with a movable contact 36 carried by the lever 34. A rubbing block 31 and one end of a leaf spring conductor 38 are mounted on the lever 34, the other end of the spring 38 being attached to an insulated terminal 38. The rubbing block 31 is operated by a cam 48 formed integral with the sleeve 3|.

If the housing 20 is rotated about the axis of the shaft 24, the angular relation between the rubbing block 3'! and the cam 40 will be varied in order to vary the timing of the ignition. The timing of the ignition will be varied also by changing the angular relation between the sleeve 3| and the shaft 24; this change being effected centrifugally by the means responsive to engine speed including the weights 2'! and the associated mechanism. It will be understood that the circuit interrupter terminal 39 is connected to the primary winding of an ignition coil and that the distribution of sparking impulses generated by the coil is effected by distributor apparatus comprising a distributor rotor 4| that cooperates with a central terminal 42 and a circular row of terminals 43, the former being connected with the secondary winding of the ignition coil and the latter terminals 43 being connected with the engine spark plugs. The terminals 42 and 43 are carried by a noncondueting cap 44 cooperating with the housing 28 to enclose the ignition timing and distributing apparatus.

Other means for automatically controlling the timing of the ignition comprises a suction chamber 50 made of sheet metal parts 5| and 52 enclosing and supporting afiexible diaphragm 53, the edges of which are clamped between peripheral portions of the parts 5| and ,52. The diaphragm 53 is connected by a rivet 54 with a cup shaped washer 55 and a. bar 56. The diaphragm 53 is held in the position shown in Fig. l by a spring 51 that bears at one end against the washer 55 and at the other end against a coupling 58 threaded at 58 into a bushing 60 carried by the part 52. The coupling 58 is adapted to receive a pipe 6| attached by connections 62 to a threaded opening 63 in a carburetor frame 64. The opening 63 communicates with a port 65 drilled through the carburetor frame, which port is at a point near the edge of the throttle valve 66 so that when the valve is in the closed or idle position the port will be on the engine side of the valve 66, and so that when the valve is open to any point beyond idling or low engine speed the port will be on the carburetor side of the valve. The valve 66 is mounted on a shaft 61 that is operated in any suitable manner.

-The part 5| of the suction chamber 50 is attached by studs 68 and nuts 69 to a bracket 10 having a portion 1| pivoting about the shank 2| of the ignition timer housing 20 and resting upon a finished surface 12 provided by that portion 13 of the engine frame that provides the opening 22 for receiving the shank 2|.

Mounted upon the shank 2| and in super-imposed relation with part ll of bracket 10 is a bracket 14 that is adapted to be clamped to the shank by screw 15 and nut 16. Pivotally secured by a screw 71 and a nut 18 to an extension 19 of the bracket '10, is a cam follower or lever 88 that carries a roller 8| disposed in a cam slot 82 in an extension 83 of the bracket 14. This assembly is slidably held together by a screw 84 and a nut 85 as illustrated in Fig. 3. The bar 56 which is attached to the diaphragm 53 has a bifurcated end 56 that straddles the cam follower 80, and is secured thereto by a pin 86 passing through and cooperating with a cam slot 81 formed in the cam follower.

In operation; when the throttle valve 66 is closed or substantially closed as in engine idling the vacuum at the port 65 will be relatively high, thus overcoming the spring 51 causing the diaphragm 53 to move upwardly as viewed in Fig. 1. As the diaphragm 53 moves upwardly or compresses the spring 51, the bar 56 also moves causing the lever 88 to pivot about the screw 11 and move the roller to the inner end of the actuator or cam slot 82. This causes a relative angular movement of brackets 18 and 14 that results in shifting the housing 20 relative to the shaft 24, thereby causing the ignition circuit interrupter to be displaced angularly relative to the cam 40.

The present ignition apparatus is provided with three or more sets of means for controlling the ignition timing; namely, means for controlling in accordance with variations in engine speed, means for controlling in accordance with variations in engine load and/or engine produced suction, and means for manually controlling in order to suit other variations in operation.

Manual control of the spark timing cam can be effected by moving a Bowden wire 88 attached aromas at l! to an extension I. of the bracket II, the Bowden wire being incased in a flexible tube 90. To provide for oscillatable movement the bracket II is held down upon the engine frame 23 by a screw stud 9i threaded into a tapped hole in the engine frame 23. The head of the screw stud 8i passes through an arcuate slot 92 in the bracket Ill and retains a spring 93 bearing against a washer 94 which bears against the bracket II.

Referring to Figs. 4, 5 and 6, which show a modification of the previous forms, suillx "0 will be added to the reference characters for indicating similar parts. It is deemed unnecessary to describe structure other than those features illustrating the modifications in the second form. With particular reference to Fig. 4, bar 560 has a right angle portion Hill for cooperation with a cam element llll integral with a bracket "a which is adapted to be clamped to a shank Ila by a screw 15a. and a nut 16a. Formed upon the bar 56a is a rib portion I02 for frictional engagement with that portion of the cam element |0l that is adjacent the bar 56a. A coil spring I03 is provided and has one end anchored at I to the bar 56a in close proximity to the angle portion Hill. The other end of the spring is anchored to a pin I05 that is carried by the cam element 10!. The function of the spring being to keep surface l0l' of cam element llll and surface I00 of angle portion Hill in engaging relation.

In operation, as in the previous form, the high vacuum at the port 65a overcomes the spring 510 causing the diaphragm 53a to move the housing 20a. angularly with respect to the unit 500, through the cam elements I00 and IN. This action causes cam element "H which is integral with the clamping portion 14a. to move in a clockwise direction causing the housing 20a to be moved relative to the shaft 24a thereby causing the ignition circuit interrupter to be displaced angularly relative to the cam 40a. The slot 92a formed in the cam element IOI receives the hold-down screw 9|a surrounded by a spring 93a bearing against a washer 94a which in turn bears against the cam element HH, and permits free movement of the said cam element.

In the instance of both forms of disclosure, the angularity and/or the contour of the cam portions of the articulated connection, are designed in accordance with the power curves of different types of engines. Any changes neces sary for adapting the timer and its control unit to engines characterized by different power curves, will involve a change in but one of the physical elements, that being the configuration of the cam part 82 in the first form of disclosure, and the cam part III! in the second form of disclosure.

Solely for purposes of illustration, and presupposing a specific instance in which the control means is installed for effecting a retard in spark timing during engine idling conditions, let it be assumed that the direction of cam rotation is counter-clockwise as indicated by the arrow A in Fig. 1, and that the port 65 is on the engine side of the throttle valve 66. It will then be apparent by consideration of Figs. 1 and 4 of the drawings, that actuation of the displacement member 53 will result in oscillating the plate I4 in a counter-clockwise direction, which in turn will carry with it the movable part of the circuit breaker, thereby causing a delayed occurrence of the spark timing relation.

On the other hand, presupposing a specific instance in which the control means is installed for effecting an advance in spark timing at engine speeds above those of idling, then let it be assumed that the direction of cam rotation is clockwise, and that the port 65 is on the carburetor side of the throttle valve. It will then be observed by referring to Figs. 1 and 4 that the displacement member is not actuated until the throttle valve 66 is opened sufliciently that the port 65 is subjected to the reduced pressure of the induction pipe. The displacement member 53 and its linkage then oscillates the circuit breaker against the direction of cam rotation, thereby producing an advance in spar timing relation.

In like manner, by connecting thejsuction chamber ill tothe engine side of the throttle valve for clockwise rotation of the cam, or? by connecting the chamber to the carburetor side of the throttle valve for counter-clockwise rotation of the cam, etc., various other combinations of spark retard and advance can be obtained,

' and by modification of the camming elementsin the linkage between the displacement member and the circuit breaker support, the spark timing control may be made to follow any desired curve of engine characteristics.

While the forms of embodiment of the present invention as herein disclosed, constitute preferred forms, it is to be understoodthat other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. In ignition control apparatus for internal combustion engines having a housing provided with a shank and rotatably supported for altering the time relation of the engine, the combination with the housing comprising a plate pivotally mounted upon said shank providing for manual distributor adjustment, a second plate rigidly mounted upon the shank, and means operatively connecting the plates comprising, a cam slot in the rigid plate, a cam follower riding in the cam slot and pivoted upon said first plate, and a member carried by said first plate and connected to said cam follower.

2. In ignition control apparatus for internal combustion engines having a housing with a shank rotatably supported for altering the timing of the engine, the combination with said housing comprising a bracket pivotally mounted upon the shank, housing shifting means carried by the bracket, a second bracket having a camming surface formed integral therewith and mounted upon said shank in juxtaposition with said pivoted bracket, and a reciprocating means connected to the housing shifting means and cooperating with said camming surface.

3. In ignition control apparatus for internal combustion engines having a housing and a shank rotatably supported for controlling the timing or the engine, the combination with the shank comprising means for rotating the shank on its support, means connecting the rotating means with the shank in order to vary the angular relation of the spark timing, said connecting means comprising, a plate pivotally mounted upon said shank providing for manual distributor adjustment, a second plate rigidly mounted upon the shank, and meansoperatively connecting the plates comprising. a cam slot in the rigid plate, a cam follower riding in the cam slot and pivoted upon said first plate, said rotating means being 0 an aperture in registry with the slot, a tension device including a stud disposed in the slot and aperture and threaded into the engine frame, a shifting device carried by the bracket for varying the angular reiation between the bracket and arm, means extending from the shiitin; means to engage the cam arm, and mean: causing the cam arm to iollow the extending means upon actuation of the shifting means.

JAMELARTHUR.

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