US2383898A - Ignition control - Google Patents

Description

.Aug. 28, 1945. s. ,M. UDALE IGNITION CONTROL Filed Jan. 22, 1945 2 Sheets-Sheet 1 QUBQQ I N NW INVENTOR.

S. M. UDALE Aug.. 28, 1945.

IGNITION c Filed Jan. 22, 1945 2 Sheets-Sheet 2 Patented Aug. 28, 1945 George M. Holley and Earl Holley Application January 22, 1945, Serial No. 574,012

'1 Claims. (01. 123 1 17) The object of this invention is to advance the spark at part load to retard the spark at idle and to partially retard the spark at high manifold air pressures.

Figure 1 shows the invention applied to the ignition control of an ordinary supercharged engine used at sea level and up to 10,000 feet.

Figure 2 shows a modification to adapt the device-for engines used at altitudes in excess of 10,000 feet. 1

Figure 3 shows an alternative construction for application to a variable Venturicarburetor.

' In Figure 1, air enters at [6 and flows through the Venturi H to the superchargerl2 past the throttle l3. A port I4 is located adjacent to and on the atmospheric side of the upstream lip of the throttle l3 when closed to the idling. position. The opening I5 is located adjacent to and .on the engine side of the downstreamlip of the throttle l3.when closed to the idling position. The diaphragm'l6 is responsiveto the pressure differences at the ports 14 and I5 and controls a :06. 32.

I1 is a connection on the pressure side of the supercharger 12. This pressure istransmitted through a pipe l8 to a chamber I9 where a piston 26 reciprocates. A spring 22 engages with the piston 26 and a spring -2l engages with themaphragm l6 and thus opposes the spring 22 through the rod 32. An adjustment 23 regulates the springs 2| and 22. A stop 24 limits the idling position of the rod 32, which rod is connected to a circuit breaker 25. When the device is used on an airplane, a connection I! leads to a chamber 26 (Figure 2), in which is located a barometric element 28, controlling a valve 29 so that the pressure in the pipe I8 is less than the supercharger the diaphragm 49. When the throttles 34-35 assume the idling position, valve 4| rises and permits the passage 43 to communicate with thepassage 50, which communicates with the chamber 5|.below the diaphragm 49.

Passage 52 communicates with the air entrance 33'and through a restriction 53 with the passage 41. Passage 52 communicates through a restriction 54 with the passage 50. An adjustment 55 regulates the springs 56 and 51." Stop 58,1imits the upward travel of the diaphragm 49. An eccentric 59, controlled by a lever 60, limits the downward travel of the diaphragm 49.v Fuel enters at 6| and flows into a chamber 62, controlled by two valves63-64. These valves are controlled by the diaphragms 6566. The pressure acting on the diaphragms 65-66 is the pressure existing in the air entrance 33, which is admitted through I the passage 61. Passage 68 connects the two air chambers 69 and 10 together. Fuel passage H is controlled by the movable needle 12, which is moved by the lever '13 and the push rod 14.

Operation of Figzmes 1 and 2 At idle, the spark is retarded, say to 4 at 550 revolutions per minute. At maximum advance, the advance is to 45 (part throttle cruise), and at wide open throttle, the advance varies, say from 30 at 40 Hg to 35 at 35" Hg. Thesefigures vary with each engine, but the higher the pressure, the lower the spark advance.

At altitude (25,000 feet) the, spark retard under the influence of 30" Hg, manifold air pressure will be too great with Figure 1 because the piston will be acted upon by a 15" Hg pressure difference. With the construction shown in Figure pressure in H. The pressure in the pipe l8 escapes through an opening in the piston 20. The stop 3| limits the advance (the maximum possible under cruising conditions) of the ignition system. At idle, the maximum retard is determined by the stop 24. The adjustment 23 takes care of the intermediate spark position during variable load.

In Figure 3, 33 is the air-entrance, 34 and 35 are the variable Venturi throttles geared together by the gears 36 and 31. 38 is a fuel passage discharging between two Venturi throttles 3435. The lever 39 carries an adjustable stop 40, which engages with a valve 4|, which is held on its seat by the spring 42. Passage 43 communicates with the chamber 44 to the right of the throttle 34 and communicates through a passage 45 with the throat of the variable Venturi. which contains the spring 42, communicates with the passage 41 and with the chamber 49 above Chamber 46,

2, the Hg pressure will expand .the element 28 and the valve 29 will restrict the flow of compressed air. At sea level, the two devices should be adjusted to give the same advance for the same manifold air pressure. At altitude, it is desirable that the same absolute value of supercharger pressure controls the advance to give the same advance as that found desirable at sea level with the same pressure.

Operation of Figure 3 As the throttle is closed towards the idling position, the adjustable stop 40 engages with the valve 4!, which rises and cuts off the connection between chamber 44 and chamber 48 so that the pressure in the chamber 48 becomes atmospheric because of the opening 53. Simultaneously, suction is applied to the chamber 5| through the pipe 59. Therefore, the diaphragm 49 is drawn down and the spark is retarded. The limit of the retardation due to the idle suction is regulated by the lever 60 and the cam 59, which acts as a stop. As the throttle opened to the position shown in the drawing, the valve 4! is seated by the compression spring 42, and in the position shown, suction from the Venturi passage 45 is transmitted through the passage 43 to the chamber 48, which is located above the diaphragm 49. Diaphragm 49 is thus drawn upwardly and the rod 32 is drawn upward, advancing the spark as far as possible. The limit to the advance of the spark on the part load is determined by the stop 58. When the throttle approaches wide open, the spark assumes an intermediate position, determined by the two springs 56 and 51. This position is determined by the adjustment 55.

What I claim is: r?

1. In a spark control device for an engine having a circuit breaker, comprising an air entrance leading to the engine, a throttle valve therein, a first port in the air entrancelocated on the atmospheric side of the throttle when the throttle is closed to the idlingipositio'n, .a second port located on the engine side of the throttle when the throttle is closed to the idling position, a diaphragm. responsive to the pressuredifierences between the two ports, said diaphragm being mechanically connected to said circuit breaker, means whereby when the throttle is opened, the first port is placed on the engine side of the throttle and the second port is placed on the atmospheric side of said throttle, two stops, one for limiting the spark advance when the throttle is opened and the other for limiting'the retard when the throttleis closed to the idling position, two yieldable opposed means for moving the diaphragm in each direction and for holding. the diaphragm in an intermediate position when the throttle is opened towards the wide open position.v '3 1" 2. A device as set forth in claim 1' in which there is a supercharger connected to the air entrance, a chamber, a passage connecting the supercharger and said chamber, a moving wall in said chamber, said moving wall being mechanically connected to said circuit breaker as to move the circuit breaker towards its retarded position on an increase in supercharger pressure.

3. A device as set forth in claim 1 in which there is a supercharger connected to the air entrance, a chamber, a passage connecting the supercharger to the chamber, a second chamber, a moving wall therein, a passage connecting the two chambers, a valve in said passage, a barometric element in said first chamber connected to said valve, said moving wall being mechanically connected to said circuit breaker so as to move the circuit breaker towards its retarded position on an increase in supercharger pressure and on a decrease in altitude.

4. In a spark control device for an engine having a circuit breaker comprising an air entrance, a throttle valve therein, an air chamber, a diaphragm therein dividing said chamber into two parts, a passage connecting the first part with the suction on the engine side of said throttle, a passage connecting the second part with the pressure existing in the air entrance, valve means interconnected with said throttle for reversing these connections when the throttleis in itsidling position, two yieldable means engaging with said diaphragm so as to oppose its movement in either direction and for opposing the engine suction, a connection from the diaphragm to the circuit breaker.

5. A device as set forth in claim 4 in which there are two adjustable stops limiting the travel of the diaphragm in each direction.

6. A ,device as set forth in claim 4 in which there is an adjustment for adjusting the springs opposing the movement of said diaphragm in either direction in response to said engine suction.

'7. In a spark control device for an engine having a variable Venturi throttled carburetor comprising an air chamber, a diaphragm therein dividing said chamber into two parts, a passage connecting the first part to the suction existing in said venturi, valve means'operated by said throttle adapted to second part of the chamber ,to suction existing in the venturi so as toreverse said connection when the.throttle is in idling position, two yieldable means for opposing the movements of said diaphragm, a connection from said diaphragm to said spark control device.

STANLEY M. UDALE,

Images