US2698010A - Combined vacuum ignition spark advance - Google Patents

Description

1954 F. w. HARTMAN, JR., ETAL 2,693,010

COMBINED VACUUM IGNITION SPARK ADVANCE Filed June 10, 1953 II/IIIIII Frank WHart/man Jr. 5 Kali)? hSiJofinson INVENTORS I BY H M5;

9 T TOR/V5 y United States Patent Ofifice 2,698,010 Patented Dec. 28, 1954 COMBINED VACUUM IGNITION SPARK ADVANCE Frank W. Hartman, Jr., Huntington Woods, and Kalin S.

Johnson, Northville, Mich., assignors to Holley Carburetor Company, Detroit, Mich., a corporation of Michigan Application June 10, 1953, Serial No. 360,676

1 Claim. (Cl. 123-117) The object of this invention is to advance the low tension ignition timer and the distributor of high tension current to the individual spark plugs equally with every increase in speed and for every decrease in inlet manifold airv pressure so that they never get out of step. Usually the low tension timing goes ahead of the high tension distributor. I

Figure 1 shows in plan view the view looking down on Figure 2.

Figure 2 shows in cross-sectional elevation the preferred form of our invention.

In the figures: is the circuit breaker cam. 11 is the driven shaft. 12 is the driving shaft. 14 is the passage through which inlet manifold suction is applied to the two casings 16 and 18 mounted on the plate 21. and 17 are two supporting plates of the two.

Plate 21 is mounted on and driven by the driving shaft 12. and 22 are the two fabric flexible portions of the two diaphragms in the casings 16 and 18. 28 is a cross bar mounted on the driven shaft 11. 24 and 26 are the two tension springs which pull the cross bar 28 anti-clockwise to retard the spark. The clockwise rotation of this cross bar 28 rotates the driven shaft 11 and the cam 10 so as to advance the spark and to advance the high tension distributor arm 31 mounted on the end of the high tension distributor shaft 32.

30 is the low tension circuit breaker arm. 34 is the inlet manifold. 36 is the throttle valve. 38 is the suction pipe. 40, 42 are the vacuum chambers. 44 and 46 are two weights attached to 15 and 17.

Operation Centrifugal force acting on the two discs 15 and 17 in the middle of the two diaphragms 20 and 22 tends to ad- Vance the timing of the cam 10 and the position of the distributor arm 31. Suction introduced through passage 14 serves to advance the spark as the inlet manifold pressure falls. As speed increases, the centrifugal force of the supporting plates 15 and 17 and the weights 44 and 46 in the middle of the two diaphragms 20 and 22 rotate the driven shaft. As the inlet manifold pressure falls, the atmospheric pressure assists the centrifugal efiect by suction being conducted through pipe 38 from the inlet manifold 34 through passage 14 to the two suction chambers 40 and 42.

It will be noted that the pipe 38 transfers the atmospheric pressure to the inlet manifold pressure (suction) whenever the throttle 36 moves away from the idle position in which it is shown.

In a V-l2 or V-8 engine the high tension terminals in the high tension distributor must be spaced 30 and 45 apart. With modern engines (overhead valves) the maximum spark advances required increase the dangers of firing in the wrong cylinder unless, as in this invention, both the low tension cam 10 and the high tension distributor arm 31 are advanced equally.

What we claim is:

In an ignition system for an internal combustion engine having a throttle controlled inlet manifold comprising a driven shaft, a low tension timing cam, 21 high tension distributor both rigidly connected to and mounted on said shaft, a driving shaft, a passage therein, a connection through which inlet manifold suction can be introduced into said passage, a rotating plate mounted on said driving shaft, a pair of suction chambers mounted on said plate located symmetrically so as to face each other and both connected to said suction passage, a moving wall in each chamber having a substantial weight, a cross bar connected to said driven shaft, two links connected with the two ends of the cross bar and to the two moving walls, spring means adapted to oppose the effect of the suction and centrifugal forces of the two moving walls on the driven shaft which rotate it so as to advance the driven shaft and thereby advance equally the low tension timing cam and the high tension distributor arm with reference to the driving shaft.

No references cited.

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