US1859309A - Contboii device fob iqnitioit timers - Google Patents

Description

-May 24, 1932. M. MALLORY CONTROL DEVICE FOR IGNITION TIMERS Filed Oct. 12, 1931 gwoentoc Patented May 24, 1932 nBION MALLORY, OF TOLEDO, OHIO (DNTBOL DEVICE FOR IGNITION TIMEBS Application filed October 12, 1931. Serial No. 568,287.

This invention relates to a control device for ignition timers, with particular reference to the condition present when, with the engine idling, the t rottle is suddenly o ened.

In order to insure a smooth and stea y operation when the engine is idling, it is necessary to set the timer so that the spark will occur when the crank is 5 to 10 past dead center. With such setting, when the throttle is open, if the initial spark advance depends primarily upon a centrifugal governor, no advance will take place until there has been a considerable increase in'speed and as a consequence the fpick-up will be slow. On the other hand, i the spark is initially set where it should be for the best performance after the throttle is opened, it Wlll cause the operation of the engine to be jerky when idling or perha s to stop altogether.

Wit the above facts in mind, it is the object of the present invention to control the timing automatically in such a manner that in idling the spark will occur when the crank is at an appreciable angle past dead center, but when the throttle is opened, the spark will be immediately advanced so that it will occur before the crank reaches dead center. The subsequent control of the timing as the speed of the engine increases may be effected by any suitable means. That is, it may be controlled solely by a centrifugal governor, by the vacuum in the fuel intake, or by a combination of both, or it may be controlled manually b a connection withthe throttle or indepen ently thereof.

The present embodiment of m invention will be more articularly descri ed in connection with the accompanying drawings, in which- Figure 1 is a vertical sectional view of a timer with which the invention is associated;

V Figure 2 is a section taken on the line 2-2 of Figure 1;

Figure 3 is a section takenon the line 33 of Figure 1;

. Fi of Figure 1; and

Fi re 5 is a section of the timer similar to Figure 4, but shows in connection therewith a modified form of the invention.

re 4 is a section taken on the line As shown in the drawings, the invention is associated with an ignition timer comprising a housing 10 formed with a bearing 11 for the timer shaft 12. A sleeve 13 is mounted for relative circumferential movement on the shaft 12 and is provided with a cam 14: which actuates the circuit breaker 15. The relative position of the sleeve 13 and cam 14 with reference to the timer shaft 12 is controlled through the medium of a circular plate 16 which is secured to the sleeve other suitable means.

The position of the plate 16, as the speed of operation increases, is usually controlled by screws 17 or by a suitable centrifugal governor which, in u 21 which 70 which is eccentric to the axis of the weight 75 so as to cause an advance movement of the plate 16 and circuit breaker 14 as the weight is moved outwardly under the influence of centrifu a1 force.

In or ance with the invention, when the engine is idling, the housing 10 is formed with a lateral extension 24 within which a piston 25 is operable. The piston has a stem 26 which er to control the timing in accord- 80 is adapted to project into a bore'27 extending through the wall of the housing in the same plane as the plate 16. The inner end of the stem 26, when it comes in contact with the edge of the plate 16, acts as a brake on the latter to retard the spark. The extension 24 houses a coil spring 28 which normally acts against the head of the piston to urge the latter toward the outer end of the housing, thus moving the brake out of contact with the plate 16.

The cavity which contains the spring 28 has a port 29 connected by a suitable conduit 30 with the intake manifold or some other part of the fuel intake as indicated at 31.

Thus, when the throttle is closed, so that the operation of the engine even though idling causes a considerable vacuum in the fuel intake passageway 31, the suction thus created overcomes the tension of the spring 28 and causes the inner end of the stem 26 to act on the plate 16 to retard the spark so that it will take place after the crank has passed dead center. This insures a steady operation when idling. When the throttle is opened, this immediately relieves the vacuum in the passageway 31 sufliciently to permit the spring 28 to act on the head of the piston 25 and relieve the plate 16 from the action of the brake. The result is that whenever the throttle is opened the spark is immediately advanced so that it occurs at 5 or 10 in advance of dead center and its subsequent timing will, in the present instance, be controlled by the normal action of the centrifugal governor. When the engine is operating at high speed, there may be suflicient vacuum in the intake to again apply the brake but by that time the centrifugal force on the governor will be suflicient to overcome the friction of the brake and hold the spark advanced.

In the modification shown in Figure 5, the same retardation of the spark, when the engine is idling, is eflected directly through the operation of the throttle rod 32 by which the throttle valve 33 is controlled through .the medium of the arm 34. In this construction the throttle rod 32 is connected by any suitable means with a rocker arm 35 mounted on a bracket 36 located adjacent the extension 24. The end 37 of the rocker arm 35 is adapted to engage the end 38 of the piston 25, which projects beyond the end of the extension 24. As shown, there is a lost motion between the throttle rod 32 and the rocker arm 35. As the throttle rod 32 is advanced to close the throttle valve 33 for idling, it rocks the arm 35, causing the end 37 to engage the projecting end of the piston and to move the brake into frictional contact with the plate'lfi, thus retarding the spark. As soon as the throttle rod 32 is moved in the opposite direction to open the throttle valve 33 either partially or fully, the piston 25 is immediately under control of the spring 28 and the brake is withdrawn from contact with the plate 16.

From the foregoing description, it will be seen that I have provided a timer controlling device which may be initially set so that in idling the spark will occur after the crank passes dead center and yet, the moment the throttle is opened, the brake is moved to inoperative position, permitting the spark to advance immediately to a normal position 5 or 10 in advance of dead center, after which it may be controlled in any suitable manner in accordance with the speed of the engine or other conditions under which the engine is operated.

It will be understood that the invention may be further modified in various respects without departing from the scope of the invention as defined in the claims.

What is claimed is:

1. In an internal combustion engine, the combination with a timer shaft and a circuit breaker cam movable circumferentially with respect thereto,'said cam being initially set for causing a spark after passing dead center position when the engine is idling, of means for immediately advancing the cam, when the throttle is opened, to-cause the spark to occur in advance of dead center position.

2. In an internal combustion engine, the combination with a timer shaft and a circuit breaker cam movable circumferentially with respect thereto, of means acting on said cam to delay the spark only when the engine is idling.

3. 11 an internal combustion engine, the combination with a timer shaft and a circuit breaker cam movable circumferentially with respect thereto, of means rendering the timing later than normal only when the engine is idling.

4. In an internal combustion engine, the combination with a timer shaft and a circuit breaker cam movable circumferentially with respect thereto, of means for normally controlling the timing in accordance with the speed of the engine, and means rendering the timing later than normal only when the engine is idling.

5. In an internal combustion engine,- the combination with a timer shaft and a member including a circuit breaker cam movable circumferentially with respect to the shaft, of a brake, and means for applying the brake to said member only when the engine is idling.

6. In, an internal combustion engine, the combination with a timer shaft and a member including a circuit breaker cam movable circumferentially with respect to the shaft, of

8. In aninternal combustion engine, the 1 combination with a timer shaft and a member including a c'rcuit breaker cam movable circumferentiall y with-res ect to the shaft, of a brake operable by suction from the fuel intake passage of the engine to engage said

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