US2087339A - Ignition apparatus - Google Patents

Description

July 20, 1937. J. L. ARTHUR IGNITION APPARATUS Filed Dec. 50, 1931 2 Sheets-Sheet 2 Patented July 20, 1937 UNITED. STATES PATENT OFFICE IGNITION APPARATUS ware Application December 30, 1931, Serial No. 583,907

13 Claims.

This invention relates to ignition apparatus for internal combustion engines and more particularly'to devices for controlling the timing of the ignition in accordance with engine speed and engine load conditions.

A centrifugal control which is constructed to give approximately correct timing in response to variationsin speed for certain loads will not be correct for other loads. For example a centrifugal control constructed for full load operation will not give suflicient advance for part load operation, and will not provide sufiicient retard for engine idling.

It is one of the objects of the present invention to efiect a greater spark retard at idling speeds than is possible alone with a centrifugal control constructed to take care of operations at a certain load, preferably full load, in order that the engine will idle more steadily and will not tend to stall. Another object is to obtain a greater spark advance under part load operating conditions than is possible with said centrifugal control alone in order to obtain better fuel economy. In order to accomplish these objects I provide in addition to the centrifugal spark control, a double acting control operated byengine suction. In the disclosed embodiment of the invention I provide a diaphragm dividing a housing into two suction chambers, the diaphragm being held in normal or center position by one or more springs which resist movement of the diaphragm in either'direction normally. A suction chamber on one side of the diaphragm is connected with a port in the engine fuel passage the port being located in the proximity to an edge of the throttle valve when closed and being located on the engine side of the valve. The other suction chamber is connected with a port in-the fuel intake passage said port being located in proximity to an edge of the throttle valve when closed and on the carburetor side of said valve. When the engine is idling there will be a vacuum in that suction chamber which is connected to the port on the engine side of the throttle valve; and that vacuum will operate to retard the ignition in order to give smooth engine operation whileidling. When the engine is operating at part load the suction in the first mentioned suction chamber will be relatively low and hence inoperative to retard the ignition; but the suction in the other chamber connected to the port on the carburetor side of the throttle valve will be operative to advance the ignition to a greater extent than possible with the centrifugal advance alone.

With wide open throttle, the vacuum is very low at either port; hence, neither suction device will be operative to advance or retard the ignition and the timing will be controlled by the centrifugal devicealone.

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 one form of the present invention is clearly shown.

In the drawings:

Fig. 1 is a diagrammatic plan view of the apparatus embodying'the present invention certain parts being shown in section taken on the line l-l of Fi 4.

Figs. 2 and 3 are charts illustrating the opera tion of the invention.

Fig. 4 is in part a longitudinal sectional view of an ignition timer to which the present invention, which is shown in side elevation, is attached.

Figs. 5 and 6 are sectional views taken on the lines 55 and 6-6 of Fig. 4.

Fig. 7 is a sectional view of a suction operated device which is a modified form of that shown in Figs. 1 and 4.

Referring first to Fig. 4, 20 designates an ignition timer housing-having a shank 2| which provides a bearing 22 for an ignition timer shaft 23 driven bythe engine in any suitable manner. The shank 2| includes a bearing portion 24 received by a well provided by the engine frame 25. The shaft 23 drives a weight plate 26 carrying studs 21 upon which are pivotally mounted weights 28 having arms 29 which cooperate with levers 30 carried by a sleeve 3| which provides an ignition timer cam 32. The. weights 28 are urged inwardly toward the shaft 23 by springs 33 attached to studs 21 and to studs 34 carried by the levers 30. One at least of the studs 34 is extended and projects through an enlarged aperture 35 in the plate 26 to act as a rotation stop for the centrifugal mechanism, all as is substantially shown and described in the U. S. Patent No. 1,825,388 to J. T. Fitzsimmons.

Referring also'to Fig. 1 the cam Iii {engages a rubbing block 40 carried by an ignition circuit breaker lever 4| pivoted at 42 and insulated from ground connections 'and carrying a contact 43 engageable with a grounded contact 44. The rubbing block 40 is urged toward the cam 32 and current is conducted to the circuit breaker lever 4| by a leaf spring conductor 45 attached at one end to the lever 4| and at the other end to an insulated strip 46 connected with an insulated terminal 41. The cam 32 drives a rotor 50 carrying a segment 5I cooperating with distributor posts 52 carried by distributor head 53 which carries a center contact 54 engageable with a button 55 carried by a leaf spring 56 electrically connected to the segment 5| and driven by the rotor 50.

The portion 24 of the timer housing shank 2| is embraced by a clamp comprising members 60 and 6| forced together by a screw 62 and a nut 63 which when tightened secures the clamp to the portion 24. The clamp includes an arm 65 carrying a swivel stud 66 through which passes a wire 61 secured to the stud by a screw 69.

A hold-down bracket 10 surrounds the shank portion 24 and is located above the clamp arm 65. The plate 10 is provided with an arcuate slot H which receives a screw 12 threaded into the engine frame 25 as shown in Fig. 4. The head, of the screw 12 has a shank portion passing through a spring 13 and a washer 14. The spring 13 yieldingly urges the washer 14 and the hold-down plate 10 against a machined surface 16 of the engine frame 25. The plate 10 carries a swivel stud 11 through which passes a wire 10 attached to the stud by a screw 19. The wire 18 passes through a spiral wire tube 80 and hence to a,

manual control knob or lever in convenient reach of the driver for the purpose of manually adjusting the timing of the ignition. The plate 10 is provided with a notch defined by surfaces 9| and 62 which serve as stops to limit the movement of the swivel stud 66 in either direction when controlled by the suction device which will now be disclosed.

The suction device comprises housing members 90 and 9I the former being attached by screws 92 or otherwise to bracket 99 integral with the plate 10. The bracket 93 is apertured to receive a bushing 94 through which the wire 61 passes, the bushing 94 being secured to the housing 90. The housings 90 and 9I are provided with peripheral flanges 95 and 96 between which the periphery of a diaphragm 91 is clamped, the flange 95- being spun over at 98 against the flange 96 to secure the parts in position. The wire 61 is attached to a rod I00 which is provided with a shank IOI which serves as a rivet to attach to the rod I00 two washers I02 and I09 and between them the diaphragm 91 through which the shank IOI passes. The diaphragm 91 may be made of thin flexible metal or of layers of varnished aeroplane linen or the like. The housing 9I carries an intemaliy threaded bushing I 04 which receives a cap I05 to which a fitting I06 secures a pipe I01. The pipe I01 is connected by fitting I09 with a fuel intake pipe 0 or carburetor framehaving a port III communicating with the pipe I01. The port III is located so that it will be just above the lower edge of the butterfly throttle valve II2 when in closed position indicated at II2a. The valve H2 is carried by a shaft H3 which is manually operated in any suitable manner. The housing 90 carries a threaded bushing II5 to which a coupling I I6 secures a pipe II1 secured by coupling I I9 to. the fuel pipe I I 0. The pipe IIO carries a port I I 9 in communication with pipe I I1 and located below or on the carburetor side of the valve II2 when in the closed position 'II2a.

Motion of the diaphragm 91 in either direction is resisted by one spring I20 in the form of invention shown in Figs. 1 and 4. This spring I20 bears at one end against an internal flange l2I provided by sleeve I22 having an outwardly turned flange I23 which is received by shoulder I24 provided integrally by the bushing I04. The spring I20 bears at the other end against a washer I25 engaged by the end of the cap I05.- The washer I 25 fits loosely around the rod I 00 and is retained with respect to the rod I00 by a resilient clip I26 having resilient bifurcations I21 received by groove I28 of the rod I00. Movement of the diaphragm 91 toward the right is limited by the flange I23 of sleeve I22 striking the washer I25. Movement of diaphragm 91 toward the left is limited by the washer I25 engaging the flange I29 of the sleeve I 22. These stops provided by the elements I23 and I25 are supplemental to the stops 8i and 92 for the swivel stud 66. For convenience of discussion the first may be called inside or diaphragm stops, while the second may be termed outside or distributor stops respectively. By providing the dual set of stops, there is an assurance against rupture or undue stretching of the diaphragm, this being taken care of by the inside stops, which also enables the manufacturer to turn out a structure of uniformity, and there is likewise insured, by the outside stops, means to keep the spark timing relation within certain predetermined limits irrespective of the amount or character of force exerted by the several devices to alter the basic or initial spark timing relation. Either of these sets of stops, or. .both together, provide for adapting the control devices to the timing adjustment so as to-accomplish the maximum efliciency for all conditions of engine operation. It will be appreciated that by use of either or both sets of stops, it is possible to cut oil any undesired effect or action of the engine produced suction on the pressure responsive devices.

With particular reference to the pressure re- .it is held by the sleeve I22 while the right hand end is permitted to move. until the washer I25 strikes the flange I29 of sleeve I22. In this way a single spring operates to resist movementof the diaphragm 91 in either direction,'and to retain the diaphragm normally in a central position as shown in Fig. 1.

In the form of invention shown in Figf'l two springs I30 and I II are employed for resisting movement of the diaphragm 91 to the right and to the left respectively. In Fig. 7, the housing 9Ia corresponding to the housing 9I of Fig. 1 carries a threaded bushing I04a into which is threaded a cap I054: to which the pipe I01 is connected by acoupling I06. The sleeve I22a in this form has its flange I2 Ia engaged by the left hand ends of both springs I90 and I 9|. The right hand fixed relative to the bushing I04a while the spring 15 -erly in either direction the construction shown in Fig. 7 may be used. As stated before, each spring in Fig.. 7 resists movement of the diaphragm in one direction only. However, the mode of operation of either form of invention is the same and that operation will now be described with particular reference to Figs. 2 and 3.

By use of the outside set of stops, the range of spark timing retard and advance can be determined, by the spacing of the surfaces BI and 82,

which cooperating with the swivel stud 6B limit the amount of angular adjustment between the plates 65 and I0 that may be made. The initial spark timing relation that is desired and that proves to be most efficient for the particular engine characteristics, can be accomplished by the variable connection between the swivel stud 65 and the wire 61, whichposition may be ac.- complished by means of a jig applied to one of the stops 8| or 82 and the stud.

Referring to Fig. 2 the curve ab-cde shows the vacuum atthe port I II as the throttle H2 is 'openedto increase the speed from zero to 15 or more miles per hour. The curve fegh shows the vacuum at the port II9 as the throttle is opened to increase the speed of the vehicle from 10 miles per hour to maximum. Itl-will be noted that these curves cross at point e thus indicating that, at about 15 miles per hour, the suction at the ports 'III and I I9 is equal and that this suction is approximately 7 inches of mercury. Therefore the spring I20 may be constructed and arranged so that it will not start to move in either direction until a suction of 7 inches of mercury has been obtained and that the diaphragm 97 will be moved to the fullest extent in either direction when about 14 inches of mercury vacuum exists at either port III or N9, the extent of diaphragm movement being determined by the stops.' The curve a-bcd-e cmsses the 14 inch vacuum line at points b and d corresponding, respectively, to about 3 and 14 miles per hour. Therefore, as the throttle H2 is moved from closed position into a position to cause the engine to idle at about 3 miles'an-hour the spark will be retarded from about "ll/ degrees,represented. by point 7' to minus 10 degrees as indicated at ,point kon the speed-spark advance curve Io l-m no of Fig. 3. Then as the throttle is opened wider to give the speed of 10 miles an hour the spark will not be retarded any further because the right hand end of the sleeve I22 will have engaged the-washer I25 against the cap I05, or depending on the adjustment of the stud 66 with the wire 61, the stop 82 may be engaged by 66. In either event, the retard'of' spark timing relation is cut off at one extreme of the spark timing range, which is represented in Fig. 3 by the dashed linekl. Between 3 miles and about 14 miles the vacuum increases from b to c and then decreases from c to d but the-spark retard remains the same as at point --k as indicated by the line 10-1 in Fig. 3. Then as the throttle is opened still wider to give a speed of about 15 miles an hour the vacuum at port III falls off very rapidly to point e or to about'l inches of mercury vacuum; hence, the spark is adyanced back to normal as indicated by the line lm which corresponds to the line de in Fig. 2. As the throttle H2 is opened still wider the suction at port III falls off still further and is practically negligible at speeds above 20 miles an hour. As the throttle I I2 is opened to give vehicle speeds above 15 miles an hour the vacuum at the port 9 increases until at about 30 miles it has reached a maximum of about 15 inches of mercury as indicated by point -gin Fig. 2. As

the-speed increases to between 15 and 30 miles an hour the spark is advanced to a degree which is the sum of degrees of advance obtained by the centrifugal device represented by line mo and the degree of advance effected by thesuction at the port I I9. Therefore, as the speed increases to 30 miles an hour the spark will be advanced in accordance with the curve m-n to give the best spark advance for engine economy. At speeds above 30 miles an hour the vacuum at the port II 9 decreases as indicated by the curve 57-71. At maximum speeds. the suction device adds practically no degrees of advance to the degrees of advance effected by the centrifugal device alone, hence the spark curve n-o slopes downwardly until it reaches the curve m-o at point -o--. The curve mno therefore indicates that the spark is advanced relatively rapidly between 10 and 30 miles per hour road torque (meaning the load carried by the engine when propelling a vehicle on a level road), and that the spark is retarded relatively slowly as the throttle is opened to givespeeds above about 30 miles per hour.

. Due to the characteristics of certain engines it may .not be desirable to make use of all of the advance provided by the pressure responsive device, but it will be desirable to eliminate a certain portion of its control such as that at the peak of its pressure curve. It is at this point that the other stop means, either 65 and BI or I23 and I25, come into effect. Assuming that it is desirable to cut off the control ofthe pressure responsive device between the speeds of about 18 and 40 miles per hour, so that the advance for that range will be confined to a fixed and uniform increase over the control by the centrifugal device, the ultimate spark timing advance will then follow the curve m1'so of Fig. 3, instead of mno. In accomplishing this result either one of the stops of either set will arrest movement of the diaphragm at the proper point so that there is no further angular shift between the cam and circuit breaker due to the engine produced pressure, between those selected speeds. When this occurs, the spark timing advance will be controlled in accordance with the flat portion of the curve 1- 8.

Thus the present device combining a doubleacting suction control with a centrifugal control, provides a complete automatic spark timing control which should require no attention by the driver. The manual control provided by wire I8 can be used in emergency to give additional retard if necessary. .For ordinary use the manual control 18 might be eliminated and the plate I0 clamped to the engine frame in the desired position of adjustment.

While the form of embodiment of the present invention as herei'iidisclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. In apparatus for spark timing control of an internal combustion engine, wherein an engine fuel pipe is in communication with the carburetor and engine cylinder and is provided with a butterfly throttle valve regulatory of the speed of engin operation, the combination with said engine fuel pipe, of a circuit breaker, a driving cam for operating the breaker, and means responsive to engine produced suction for varying the angular relation between the cam and breaker, said means including a suction chamber having communication with a port in the engine fuel pipe located on the engine side of the throttle valve and near an edge of the valve only when the valve is substantially closed, and including a suction chamber having communication with a port in the engine fuel pipe located on the carburetor side of the throttle valve and near an edge of the valve when closed, a common diaphragm influenced by the suction in both chambers, and spring means resisting the movement of said diaphragm in either direction.

2. In apparatus for spark timing control of an internal combustion engine, wherein anengine fuel pipe is in communication with the carburetor and engine cylinder and is provided with a butterfly throttle valve regulatory of the speed of engine operation, the combination with said engine fuel pipe of, acircuit breaker, a driving cam for operating the breaker, and means responsive to engine produced suction for varying the angular relation between the cam and breaker, said means including a suction chamber having communication with a port in the engine fuel pipe located on the engine side of the butterfly throttle valve and near an edge of the valve when closed, and including a suction chamber having communication with a port in the engine fuel pipe located on the carburetor side of the butterfly throttle valve and near an edge of the valve when closed, a common diaphragm influenced by the suction in both chambers, and two coiled springs for resisting the movement of the diaphragm in either direction respectively.

3. In apparatus for spark timing control of an internal combustion engine, wherein an engine fuel pipe is in communication with the carburetor and engine cylinder and is provided with a butterfly throttle valve regulatory of the speed of engine operation, the combination with said engine fuel pipe of, a circuit breaker, a driving cam for operating the breaker, said circuit breaker and cam being arranged in a predetermined angular relation, and means responsive to engine produced suction for varying the angular relation between the cam and breaker, said means including a suction chamber having communication with a port in the engine fuel pipe located on the engine side of the butterfly throttle valve and near an edge of the valve when closed for retarding the ignition timing from a predetermined angular relation during engine idling operation, and including a suction chamber having communication with a port in the engine fuel pipe located on the carburetor side of the butterfly throttle valve and near an edge of the valve when closed for advancing the ignition timing beyond the predetermined angular relations during engine operation under part. load condition.

4. In an internal combustion engine wherein fuel is delivered thereto through an engine fuel pipe provided with a butterfly throttle valve. ignition apparatus comprising in combination, a circuit breaker, a driving cam for operating the breaker, and means responsive to engine produced suction for varying the angular relation between the cam and breaker, said means including a suction chamber having communication with a port in the engine fuel pipe located on the engine side of the butterfly throttle valve and near an edge of the valve when closed, and including a suction chamber having communication with a port in the engine fuel pipe located on the carburetor side of the butterfly throttle valve and near an edge of the valve when closed, and including movable means influenced by the suction in both chambers.

5. A. spark timing control for an internal combustion engine wherein an engine intake pipe with a butterfly throttle valve conducts fuel from the carburetor to the engine cylinder or cylinders under pressures inversely proportional to engine speed, characterized by the fact that there is in combination, a circuit breaker, a driving cam for operating the breaker, and means responsive to engine produced suction for varying the angular relation between the cam and breaker, said means including a suction chamber having communication witha port in the engine fuel pipe which port is so located that it will be wholly on the engine side of the butterfly throttle valve and near an edge of the valve when the valve is closed and on the carburetor side of the valve when the same is at least partially open, and including a suction chamber having communication with a port in the engine fuel pipe located on the car: buretor side of the butterfly throttle valve and near an edge of the valve when closed, a common diaphragm influenced by the suction in both chambers, and'a single coiled spring resisting the movement of the diaphragm in either direction.

6. In apparatus for spark timing control of an internal combustion engine, wherein an engine fuel pipeis in communication with the carburetor and engine cylinder and is provided with a butterfly throttle val ve regulatory'of the speed of engine operation,1 the combination with said engine fuel pipe of, a circuit breaker, a driving ,cam for operating the breaker, said circuit breaker and cam being arranged in a predetermined angular relation, and means responsive to engine produced suction for varying the angular relation between the cam and breaker, said means including a servo-motor device responsive to a vacuum differential, and having two conduits leading therefrom, one of which has communication with a port in the engine fuel pipe located on the engine side of the butterfly throttle valve and near an edge of the valve when closed for retarding the ignition timing from a predetermindangular relation during engine idling operation, and the second of which hascommunication with a port in the engine'fuel pipe located on\ the carburetor side of the butterfly throttle valve and near an edge of the valve when closed for advancing the ignition timing beyond the predetermined angular relations during engine operation at speeds above idling.

'I. In an internal combustion engine wherein fuel is delivered thereto through an engine fuel pipe provided with a butterfly throttle valve, ignition apparatus comprising in combination, a circuit breaker, a driving cam for operating the breaker, and-means responsiveto ermine produced suction for varying the angular relation between the cam and breaker, said means including a servo-motor device responsive to a vacuum differential, having two. conduits leading to spaced ports in the engine fuel pipe, and a movable member influenced by the vacuum in either or both of the conduits, one of said conduits having communication with a port in the engine fuel pipe located on the engine side of the butterfly throttle valve and near an edge of the valve when closed, and the other conduit having communication with a port in the engine fuel pipe located on the carburetor side of the butterfly throttle valve and near an edge of the valve when closed.

8. In an internal combustion enginehaving a fuel pipe provided with a throttle valve, and subject to variations in engine produced suction incident to self operation, ignition apparatus comprisi' g in combination, a circuit breaker, a cam for perating the breaker and means responsive to engine produced suction for varying the angular relation between the cam and breaker, said means including a suction chamber having communication with a port in the fuel pipe located on the engine side of the throttle valve and near the edge of the valve when closed, an additional suction chamber having communication with a port in the fuel pipe located on the carburetor side of the throttle valve and near the edge of the valve when closed, and a common diaphragm influenced by the suction in both chambers.

9. In an internal combustion engine having a fuel pipe provided with a throttle valve, and subject to variations in engine produced suction incident to self operation, ignition apparatus comprising in combination, a circuit breaker, a cam for operating the breaker and means responsive to engine produced suction for varying the angular relation between the cam and breaker, said means including a suction chamber having communication with a port in the fuel pipe located on the engine side of the throttle valve and near the edge of the valve when closed, an additional suction chamber having communication with a port in the fuel pipe located on the carburetor side of the throttle valve and near the edge of the valve when closed, and a common diaphragm influenced by the suction in both chambers, the movement of the diaphragm in either direction being resisted by' spring means located entirely on one side of the diaphragm.

10. In an internal combustion engine having a fuel pipe provided with a throttle valve, and subject to variations in engine produced suction incident to self operation, ignition apparatus comprising in combination, a'circuit breaker, a cam for operating the breaker and means responsive to engine produced suction for varying the angular'relation between the cam and breaker, said means including a suction chamber having communication with a port in the fuel pipe located on the engine side of the throttle valve and near the edge of the valve when closed, an additional suction chamber having communication with a port in the fuel pipe located on the carburetor side of the throttle valve and near the edge of the valve when closed, and a common 11. In an internal combustion engine having a fuel pipe provided with a throttle valve, and subject to variations in engine produced suction incident to self operation, ignition apparatus comprising in combination, a circuit breaker, a cam for operating the breaker and means responsive to engine produced suction for varying the angular relation between the cam and breaker, said means including a suction chamber having communication with a port in the fuel pipe located on the engine side of the throttle valve and near th-eedge of the valve when closed, an additional suction chamber having communication with a port in the fuel pipe located on the carburetor side of the throttle valve and near the edge of the valve when closed, and a common diaphragm influenced by the suction in both chambers, the movement of the diaphragm in either direction being resisted, respectively, by two coiled springs, one within the othe'rl 12. In an internal combustion engine having a fuel pipe provided with a throttle valve, and subject to variations in engine produced suction incident to self operation, ignition apparatus comprising in combination, a circuit breaker, a cam for operating the breaker and means responsive to engine produced suction for varying the angular relation between the cam and breaker, said means including a suction chamber having communication with a port in the fuel pipe located on the engine side of the throttle valve andnear the edge of the valve when closed, an additional suction chamber having communication with a port in the fuel pipe located on the carburetor side of the throttle valve and near the edge of the valve when closed, and a common diaphragm influenced by the suction in both chambers, the'movement of the diaphragm in either direction being resisted, respectively, by two coiled springs, one within the other, and both located entirely on one side of the diaphragm.

13. In an internal combustion engine wherein fuel-is'delivered thereto through an engine fuel pipe provided with a butterfly throttle valve, ignition apparatus comprising in combination, a circuit breaker, a driving cam for operating the breaker, and means responsive to engine run ning conditions for varying the angular rela tion" between the cam and breaker, said means including a suction chamber having communication with a port in the engine fuel pipe located on the engine side of the butterfly throttle valve and near an edge of the valve when closed, and including a suction chamber having communication with a port in the engine fuel pipe located on the carburetor side of the butterfly valve and near an edge of the valve when closed, and a common diaphragm influenced by the suction in both chambers, the movements of the diaphragm in either direction being resisted, respectively, by two coiled springs both located entirely on one side of the diaphragm.

. JAMES L. ARTHUR.

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