US2377566A

US2377566A - Ignition timing control means for internal-combustion engines

Info

Publication number: US2377566A
Application number: US510853A
Authority: US
Inventors: Mallory Marion
Original assignee: Individual
Current assignee: Individual
Priority date: 1943-11-19
Filing date: 1943-11-19
Publication date: 1945-06-05
Anticipated expiration: 1962-06-05

Description

June 5, 1945.

M. MALLORY IGNITION TIMING CONTROL MEANS FOR INTERNAL-COMBUSTIONENGINES Filed Nov. 19, 1943 7 6 5 4. 3 2 95 6 F W2 5 E anuo P Y 0 1T 0 M M R 500 loco v INVENTOR.

Mar/0r? Ma/lary Patented June 5, 1945 UNITED STATES PATENT OFFICE IGNITION TIMING CONTROL MEANS FOR INTERNAL-COMBUSTION ENGINES Marion Mallory, Detroit, Mich. Application November 19, 1943, Serial No. 510,853

2 Claims.

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

In my prior Patent 2,268,490 I have disclosed an ignition timer for an internal combustion engine which is controlled by the pressures in the intake passageway of the engine. I have found that in many instances the part throttle suction-or vacuum is so high that the spark is too much advanced on part throttle. In many cases the part throttle suction is considerably higher than the intake passageway suction created by the venturi at high speeds and with the throttle wide open. The suction in the intake passageway also runs very high in the event the air cleaner becomes plugged and therefore the spark is too much advanced.

It is the object of this invention to produce a pressure timed ignition system which prevents the spark from being too far advanced on part throttle and which will efliciently control the advancing and retarding of the spark under all operating conditions. This object is achieved by incorporating a pressure relief valve in the passagewa'y between the suction operated diaphragm and the intake passageway.

Fig. 1 is a sectional view showing my ignition timing control means for internal combustion engmes.

Fig. 2 is a graph showing the intake passageway vacuum at various engine speeds and at part and wide open throttle.

Referring more particularly to the drawing there is shown a, carburetor provided with a, passageway l including a venturi 2 and the usual butterfly throttle valve 3 mounted on shaft 4 which is swung opened and closed by crank 5 and rod 6. The air inlet end of the carburetor is designated l and the fuel mixture outlet 8 leading to the engine.

The timing mechanism is conventional and as shown consists of the usual rotatable cam 9 which operates the electrical circuit breaker H). The circuit breaker I is mounted on the plate II which can be rotated clockwise to advance the spark and counterclockwise to retard the spark. A suction device I2 is utilized for advancing and retarding the spark. The suction device comprises a flexible diaphragm I3 backed up by a compression coil spring 14.. The diaphragm I3 is mounted in the housing l which is connected to the carburetor by conduit 16. The diaphragm is connected to plate I I by connecting rod l1, one end of which is pivotally connected as at l8 to the plate II and the other end of which is fixed to the diaphragm. The wall I 9 of the housing is perforated so that the diaphragm is subjected on the outside to atmospheric pressure; whereas, on the inside of the housing IS, the diaphragm is subjected through line 16 to the booster venturi 2 and to orifice 20 located between the throttle and venturi 2.

Conduit l 6 is connected in parallel by passageways 2| and 22 to orifice 23 in the venturi 2 and orifice 20 respectively.

Referring to Fig.2 the Venturi suction at wide open throttle is shown by the line A. At an engine speed of 3000 R. P. M. the Venturi suction is approximately five inches of mercury. The part throttl suction is shown by the line B. The part throttle suction at high engine speeds and under other conditions might go up to ten or more inches of mercury which would be too much spark advance at part throttle. In my system I have found that the part throttle vacuum should not run much higher than the Venturi vacuum at high engine speeds. Therefore, line I6 is provided with an air bleed to atmosphere comprising conduit 25 communicating with conduit "5 and provided with an orifice 26 to atmosphere. Orifice 26 is controlled by ball check 21 held against its seat by compression spring 28. The strength of spring 28 is chosen or regulated so that if the part throttle vacuum impressed upon the suction device l2 through conduit I6 is too high, valve 21 will open and bleed the suction device to atmosphere sufliciently to bring the vacuum acting upon diaphragm l3 down to, or in the neighborhood of, the vacuum created by the venturi 2 at high engine speeds.

Orifice 20 is positioned so that whenever throttle valve 3 is opened slightly beyond idle position orifice 20 will be subjected to manifold suction. The full manifold suction is not impressed upon the suction device because it is bled down through orifice 23.

The operation of my ignition system is the same as described in my Patent 2,268,490, except that air bleed valve 21 operates whenever the vacuum in conduit l6 reaches or slightly exceeds a vacuum equal to that created in conduit I6 by venturi 2 at wide open throttle and high engine speeds, such,. for example, 3000 R. P. M. Thus, this air bleed in conduit l6 definitely controls the vacuum impressed on suction diaphragm IE8 at part open throttle so that the spark will be advanced to the right degree at part open throttle.

I claim:

1. In an internal combustion engine having an intake passageway including a venturi and a throttle valve in said intake passageway on the discharge side of said venturi, the combination of an ignition timing mechanism adapted for operation to advance and retard the spark, suction responsive means connected to said timing mechanism for operating the same, a conduit connecting said suction responsive means into the venturi for applying suction to the suction device from the venturi, an orifice in the intake passageway positioned on the atmosphere side of the throttle valve when in idle position and on the discharge side of the throttle valve in partly open position, a second conduit for connecting the suction device to said orifice for applying suction to the suction device from the discharge side of said throttle valve in partly opened position, and an air bleed to atmosphere for said suction device arranged to open at a predetermined suction to bleed down the suction impressed upon said suction responsive means to a suction approximating that impressed upon the suction device by the venturi at wide open throttle and high engine speed.

2. In an internal combustion engine having an intake passageway including a venturi, a throttle valve on the discharge side of said venturi, an

asvmee ignition timing mechanism, suction responsive means connected to said timing mechanism for advancing and retarding the spark, a conduit connecting the suction device into the venturi whereby the ignition timing mechanism is controlled principally by the vacuum'created by the venturi at wide open throttle and higher engine speeds, an orifice in the intake passageway positioned on the atmosphere side of the throttle valve when in idle position and on the discharge side of the throttle valve in partly open position, another conduit connecting said orifice to the suction device for applying the suction on the discharge side of the throttle valve to the suction device whereby at part throttle the suction device is controlled principally by the manifold vacuum bled down through the conduit connected into the venturi, and air bleed means con-' nected to said suction device arranged to bleed the suction device to atmosphere whenever the intake passageway suction on the discharge side of the throttle valve exceeds a predetermined value whereby an over-spark advance under the operating conditions is prevented.

, MARION MALLORY.