US2301553A - Ignition timing control means for internal combustion engines - Google Patents

Description

Nov. 10, 1942. M. MALLORY 2,301,553

IGNITION TIMING CONTROL MEANS FOR INTERNAL COMBUSTION ENGINES Filed Dec. 11, 1941 m 3 'T l N LO Q m N I 1 H} INVENTOR. MARION MALLORY Patented Nov. 10, 1942 IGNITION TIMING CONTROL MEANS FOR INTERNAL COMBUSTION EN GINE-S Marlon Mallory, Detroit, Mich. Application December 11, 1941, Serial No. 422,488

7 Claims.

This invention relates to ignition timing control means for internal combustion engines.

The principal obje t of my invention is to control the pressures in the intake passageway of an internal combustion engine so that a single suction operated device will retard the spark timing when the engine is idling, advance the spark timing when the engine is working under light loads, and reduce the advance of the spark timing when the engine is working under full loads. This eliminates the commonly known centrifugal governor used in present day ignition systems.

Fig. 1 is a sectional view partly in elevation showing the mechanism of my ignition timing control means for an internal combustion engine.

Fig. 2 is a section along the line 2-2 of Fig. 1.

The carburetor 1, adapted for attachment to an internal combustion engine, is provided with an intake passageway 9 having an air inlet end designated 9 and a fuel mixture outlet l9 through which the fuel mixture is adapted to pass into the engine intake manifold.

The passageway 9 includes the venturi H and I for purposes of description rather than by way of limitation, a booster venturi I2 is positioned within the main venturi ll. usual butterfly throttle valve mounted within the passageway 8 on shaft 3 which is swung open and closed by the rod H and crank l5. float bowl is designated I6.

The fuel Fuel is drawn from I3 designates .the

the float bowl through passageway ll into the mixing chamber.

A conventional timing mechanism is shown consisting of the usual rotatable cam l8 which operates the electrical circuit breaker i9 mounted on plate 29 which can be rotated clockwise to advance the spark and counterclockwise to retard the spark. A suction device 2| is used for advancin'g and retarding the spark. The suction device comprises a flexible diaphragm 22 backed up by a compression coil spring 23. The diaphragm is mounted in housing 24 which is connected to the carburetor by conduit 25. The diaphragm is connected to plate 29 by rod 26, one end of which is'pivotally connected as at 21 to the plate 20 and the other end of which is fixed to the diaphragm. The wall 29 of the housing is perforated so that the diaphragm is subjected on the outside to atmospheric pressure whereas on the inside of housing 25 the diaphragm is sub- .lected through line 25 and passageway 29 and orifice 5 and passageway 2 to certain pressure conditions obtaining in and created by the intake passageway 8, as described below.

Passageway 29 communicates with conduit 25 and through orifice 6 communicates with venturi l2. If desired, passageway 29 can be connected into the large venturi I I preferably at the point of greatest restriction, that is, adjacent the lower end of small venturi l2. Passageway 29 communicates with passageway 2. Passageways 29 and 2 are both formed in the wall of the carburetor. The wall of the carburetor is also provided with a passageway 5, the inner end of which communicates with the mixture outlet III and the other end of which, at certain positions of the throttle valve I 3, communicates with the passageway 9 in the throttle, valve shaft 3, as explained below. The carburetor is also provided with a choke valve 30 mounted on shaft 3! and controlled by the usual choke rod 32.

The operation of When the engine is idling the throttle valve II will be almost closed or in idling position and conduit 2 is closed by the throttle shaft 3. At this time the suction device 2| communicates with intake passageway 3 only through orifice 6, passageway 29 and conduit 25 and the spark is retarded. as shown in the drawing, because the suction device will not be subjected'to enough vacuum to advance the ignition timer against spring 23.

As the throttle valve I3 moves toward an open position diametrical passageway 4 in shaft 3 registers with passageway 5 and with passageway 2, thereby-subjecting passageway 2 to the manifold vacuum because passageway 5 communicates with the mixture outlet l0 below throttle i3. As soon as passageway 2 is subjected to the intake manifold vacuum this, through conduit 25, sub- Jects the diaphragm 22 to manifold vacuum and the spark is advanced. If the throttle valve I3 is opened wide or near its open position, passageway 4 rotates beyond passageways 5 and 2 and passageway 2 is again shut off by the throttle shaft 3. Thus, in this system the high suction in the manifold on the engine side of the throttle I3, when operating on part throttle or part load, is reduced or bled down by the passageway 29 terminating in the venturi l 2 at orifice 6. Bleeding down the manifold vacuum closer to the vacuum created by air flowing through the venturi makes possible the. use of a single suction device. For example, supposing the manifold vacuum was not bled down, there would be approximately 14" or 15" of mercury existing in the suction device when the engine'was running at normal speeds with the throttle partly open, and unless a very stiff spring was used in the timer or suction device, the spark would be advanced too far, and, if a stifl spring were used in the timer or suction device to prevent the spark from advancing too far, the stiff spring would not permit the suction device to advance the spark when the engine was operating on wide open throttle because the maxim'umsuction in the venturi of the ordinary carburetor is never higher than 6" or 7" of mercury even at extreme high speeds. Of course, it will be understood that the manifold vacuum is not bled down to a point as the system is as followsz low as the vacuum created by the suction in the venturi because more spark advance is required when the throttle is only partly open than when the throttle is full open. The system actually produces two spark curves-one for part load and one for full load.

I claim: v

1. In an internal combustion engine having an intake manifold, a carburetor-including an intake passageway and a throttle valve therefor, a conduit having one end terminating in the intake passageway of the carburetor continuously on the atmospheresideof the throttle valve, a second conduit communicating with the first mentioned conduit, and valve means controlling the second conduit whereby the second conduit is placed in communication with the intake passageway on the engine side of the throttle valve at part open throttle and shut off from the intake passageway at idle position of the throttle, and a uction controlled ignition timing device continuously connected to the first mentioned conduit for advancing and retarding the timing of the engine ignition system as the throttle or charge is varied.

2. The combination as claimed in claim 1 wherein the valve means comprises a shaft for the throttle valve having a passageway therethrough which places the second conduit in communication with the intake passageway on the engine side of the throttle valve at part open throttle positions and which is disconnected from the second conduit at idling position of the throttle whereby the throttle valve shaft closes off the second conduit from communication with the intake passageway and the said suction device responds solely to the vacuum created by the flow of air through the said intake passageway past the end of the first mentioned conduit.

3. In an internal combustion engine having an intake manifold, a carburetor including an intake passageway and a throttle valve therefor, a venturi in said intake passageway, a conduit having one end terminating in the venturi continuously on the atmosphere side of the throttle valve, a second conduit communicating with the first mentioned conduit and with the intake passageway on the engine side of the throttle "valve, a valve in. said second conduit and a connection between said valve and the throttle valve for operating the throttle valve and the said valve coincidentally whereby the second conduit is placed in communication with the intake passageway on the engine side of the throttle valve. at part open throttle and shut ofi from the intake passageway at idle position of the throttle, and a suction controlled ignition timing device continuously connected to the first mentioned conduit for advancing and retarding the timing of the engine ignition system as the throttle or charge is varied.

4. In an internal combustion engine having an intake manifold, a carburetor having an intake passageway, a throttle valve for said intake passageway, a venturi in said intake passageway on the atmosphere side of the throttle valve; a conduit having one end terminating in the venturi of the carburetor continuously on the atmosphere side of the throttle valve, a second conduit communicating with the first mentioned conduit, and valve means controlling the second conduit whereby the second conduit is placed in communication with the intake passageway 'on the engine side of the throttle valve at part open throttle and shut off from the intake passageway at idle position of the throttle, and a suction controlled ignition timing device continuously connected to the first mentioned conduit foradvancing and retarding the timing of the engine ignition system as the throttle or charge is varied.

5. In an internal combustion engine having an municating at one end with the first mentioned I conduit and at the other end with the intake passageway on the engine side of the throttle valve, a shaft for said throttle valve, a valve carried by said shaft interposed in said second conduit for opening and closing the second conduit coincidentally with the operation of the throttle valve whereby the second conduit is placed in communication with the intake passageway on the engine side of the throttle valve at part open throttle and shut off from the intake passageway at idle position of the throttle, and a suction controlled ignition timing device continuously connected to the first mentioned conduit for advancing and retarding the timing of the engine ignition system as the throttle or charge is varied.

6. In an internal combustion engine having an intake manifold, a carburetor including an intake passageway and a throttle valve therefor, a conduit having one end terminating in the intake passageway of the carburetor continuously on the atmosphere side of the throttle valve, a second conduit communicating with the intake manifold and with the first mentioned conduit, and valve mean controlling the second conduit whereby the second conduit is placed in communication with the intake manifold when the throttle is partly open and out of communication with the manifold when the throttle is at idle position 'or near wide open position, and a suction controlled ignition timing device continuously connected to the first mentioned conduit for advancing and retarding the timing of the engine ignition system as the throttle or charge I is varied.

'7. The combination as claimed. in claim 6 wherein the valve means comprises a shaft for the throttle valve having a passageway therethrough which places the second conduit in communication with the intake manifold at part open throttle positions and closes off communication between the second named conduit and the intake manifold when the throttle is at idling position or near wide open position, whereby said suction device at part throttle positions responds solely to the manifold vacuum air-bled by the end of the first mentioned conduit terminating in the intake passageway on the atmosphere ide of the throttle valve and responds solely to the vacuum created by the flow of air through the intake passageway past the end of the first mentioned conduit at wide open throttle positions,

MARION MALLORY.

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