US1839008A

US1839008A - of dttrsley

Info

Publication number: US1839008A
Authority: US
Publication date: 1931-12-29
Anticipated expiration: 1948-12-29

Description

F. A. ATTWOOD ENGINE STARTING MEANS Filed Aug. ll, 1950 vPatented Dec. 29, 1931 UNITED STATES PATENT OFFICE;

FRANK ALBERT ATTWOOD, F DURSLEY, ENGLAND, ASSIGNOR TO R. A. LISTER & GOM- PAN Y, LIMITED, OF DURSLEY, ENGLAND ENGINE STARTING MEANS Application led August 11, 1930, Serial No.

This invention relates to electric charging plant of the kind in which the prime-mover is a compression-ignition engine.

One object of the invention is to provide improved means for ensuring the starting of the engine.

A further object is to enable the starting to be carried out automatically when the battery load registers a predetermined value.

A further object is to provide electricallycontrolled starting means which first produces super-normal compression when the engine has reached a predetermined speed, so that compression-ignition will be ensured when cold, and then restores the normal compression for straightforward running of the engine.

In the accompanying drawings, Figure 1 is a diagrammatic representation of a charging plant in accordance with the invention, and 1 Figure 2 is a part sectional elevation of a compression-ignition engine forming the prime-mover of the charging plant showing netic devices 7, 8 and 9 connected in series across the battery terminals.

One of these devices 7 is a generator switch the contacts of which connect the generator 10 across the battery terminals lwhen the device is energized.

Another of these vdevices 8, hereinafter referred to as the valve-release solenoid, is adapted to operate mechanically upon means by which the exhaust valve 11 (Figure 2) of the engine 12 is held open when the engine is at rest. The exhaust valve in the present arrangement is of the overhead type actuatrocker 15 and in order to hold the valve olf the electrically controlled means for varying ed through a tappet 13, push rod 14 and 474,625, and in Great Britain April 26, 1930.

its seat, a rotatably mounted member 16 is located adjacent the tappet and has an arm 17 projecting laterally from the upper end. On the upper surface of this arm is mounted a projection 18 and a rod 19 connects the arm to one limb 2() of a bell-crank lever pivoted at 21 to some stationary part. The other arm 22 of this bell-crank lies over the electro-magnetic device 8 and its end is adapted for engagement with the movable member 23, of the device. A spring 24 connected to the arm 20 tends always to thrust the projection 18 towards the tappet. The upper surface of the projection is such that when it engages under the table 25 of the tappet the exhaust valve will be retained in the open position until the projection is moved by the energization of the device 8 as hereinafter described. The electro-magneticdevice 8 may be arranged so that it takes a certain period of time to withdraw the projection in order to free the exhaust valve for normal operation, for example, say 8 seconds. A dashpot device 80 may be connected to this device for this purpose.

Connected in series in the generator circuit is a series field winding 26 and an electromagnetic device 27, hereinafter -referred to as a compression solenoid.

The armature 28 of this compression solenoid is interconnected with a toggle mechanism comprising two pivoted links 29'and 30 and one of these, 30, is attached to a movable valve 31 such as is shown in United States patent specification Serial No. 406,331, now Patent 1,787,326. This valve is biassed to a position in which the two compression chambers 32 and 33 of the engine are interconnected, by means of a spring 34 acting on vthe link 29 of the toggle to hold it collapsed. On the energizationfof the Winding 35 of the compression solenoid the toggle is straightened and the valve urged against the passage 36 interconnecting the two compression lleiainbers, thus cutting oii the outer cham- It will thus be seen that, with this arl rangement` as soon as the generator is connected to the battery to operate as a motor, the compression space of the prime-mover 1s materially reduced, but at the same time the exhaust valve remains open, so that the engine can be easily motored round. By the time the generator is driving the engine at a speed at- Which it can start tiring, the valverelease solenoid operates to free the exhaust valve, ,whereupon the compression in the engine reaches a figure materially above normal and ignition is ensured. The engine then begins to drive the generator.

The third of the above-mentioned three electro-magnetic devices 9 is a time-lag device. For example, it may be provided vvith a dashpot 37 by which a period of, say forty seconds elapses after its energization before it operates. On operating, it closes contacts 38, 38 connected to short-circuit the series `ield Winding 2G and the compression solenoid 27.

The de-energization ofV the compression solenoid allows the

toggle

29, 30 to collapse and the compression in the inner compression chamber 33 assists in forcing back the valve by which the compression space had previously been reduced, so that the compression space now becomes normal, including both chambers. In these conditions the engine is operating normally and driving the generator.

Any device may be provided for stopping the engine. An example of an automatic device for stopping the engine is described in the specification accompanying my copending application No.47424. This stopping device may conveniently be included 1n this plant, in Which case the first of said three devices, namely, the generator switch 7, may be arranged to control the circuit of the fuel cut off, as illustrated in said application.

It Will thus be seen that by means of the invention the automatic starting of the charging plant, as soon as the battery load reaches a predetermined value, is ensured, even when conditions are unfavourable, for example, when the Weather is frosty. Furthermore, it should be noted that the actual starting operation need only occupy a period of, say, twenty to thirty seconds, although the time-lag device 9 above-mentioned may be rated for a slightly longer time-lag in case there should be slight delay before the engine fires, and to give the engine time to settle down to its work.

iVVhat I claim as my invention and desire to secure by Letters Patent of the United/ States is 1. For starting a compression-ignitionengine, the combination of means adapted to release the engine compression, means adapted to provide a super-normal compression and means adapted to restore normal compression.

2. For starting a compression-ignitionengine, the combination of means adapted to release the engine compression, means adapted to provide a super-normal compression,

and means adapted to restore normal compression, all of said means being electricallycontrolled to operate in a predetermined sequence.

3. A method of starting a compression-ignition engine, which comprises driving the engine first at` a sub-normal compression, till it runs at firing speed, then at a super-normal compression, to ensure compression ignition, after which the compression is reduced to normal for normal running.

4. A method of starting a compression-ignition engine, which comprises driving the engine first at a sub-normal compression, till it runs at tiring speed, then at a super-normal compression, to ensure compression ignition, after which the compression is reduced to normal, for normal running, the varying compression conditions being electrically' controlled by electro-responsive devices.

5. For starting a compression-ignition engine, the combination of means operable to vary the compression space and electrical means for automatically operating said means to reduce the compression space and to restorenormal compression at predetermined times.

6. For starting a compression-ignition engine, the combination of a valve adapted to vary the compression space of said engine, a toggle mechanism connected to said valve, and electro-responsive means connected to said toggle mechanism, said electro-responsive means When energized being adapted to actuate said valve through said toggle to reduce said compression space.

7. For starting a compression-ignition engine having at least two interconnected compression spaces, a valve for isolating one compression space, an exhaust valve, means biassed to hold said exhaust valve open, electrically-controlled means for actuating said isolating valve to isolate one of said compression spaces, electrically-controlled means for withdrawing said biassed' means, and electrically-controlled means for actuating said isolating valve to restore normal running conditions after the engine has started firing.

In testimony whereof I aiix my signature.

FRANK ALBERT ATTWOOD.