Patent GB-190702509-A (GB)
Title: Improvements in and relating to Ignition Arrangements for Internal Combustion Engines and other purposes.
Inventor: HUMPHREY HERBERT ALFRED
IPC: F02P15/12
Filed: 1907-01-31
Granted: 1908-01-30
Abstract: 2509. Humphrey, H. A Jan. 31 Gas and like engines, igniting in. Relates to ignition systems for internal-combustion engines &c., in which the pressure of the compressed charge acts on a small motor which actuates a switch. Insead of the pressure at which ignition occurs being fixed for any adjustment, ignition does not occur until the pressure has reached a maximum. Fig. 1 shows a form of apparatus, adapted to produce 'one spark at the moment of breaking contact; a lever a connected to the pressure gauge extends between stops b, c on the slider d. The stop b is insulated, but the stops c are conductors making contact with strips f, f<1> on the guide and may be bridged by a spring e. As the pressure in the cylinder rises, the lever first bridges the contacts c and then moves the slider forward into position such as II. As the engine. cylinder starts its outward stroke, the pressure, having reached a maximum, begins to fall; the slight decrease causes the lever to recede from the forward stop c, breaking the primary circuit and causing a spark. The increased pressure caused by the explosion then sends the slider d forward to the position III. As the gas expands, the pressure again falls, first breaking circuit and then returning, the slider to the position I. Fig. 2 shows a form modified for use with a trembler coil. In this form, the lever a is arranged so as not to make electric contact when it is pushing the slider in either direction but only when it is passing between. these two relative positions. Both stops c, b are insulated, the contact-pieces,h, i being arranged between them. When compression begins, the lever a passes from the stop c to the stop b over the contacts h, i as there is no spark required at this time ; the contacts are arranged to be insulated, preferably, by forming the part of the guideway at I without the conducting-strips f, f<1>. As the pressure rises, the slider is carried round the guideway to position II; the lever ceases to push the slider d; and as the pressure falls slightly contact is made with contacts, h, starting the current and causing the explosion. When the pressure rises, the circuit is broken Figs. 5 and 6 show a modification adapted to be fitted to a Darke's motion indicator. The plate p carries insulating metal pillars q, r. Pivoted at v is a light lever s carrying a pin t on which is pivoted a second lever u, the motion of which relatively to the lever s is limited by stops 3, 4 carried by the latter. The piston-rod o of the indicator is attached to the lever u by a sleeve w. The end of the lever s carries metal strips h, i shown in detail in Fig., 8 attached to an insulating-block y. The lever u carries a small ball 2 which works in a groove between the strips h, i. The insulated pillar r carries an adjustable spring 5 which presses against the strip i or insulator y. As the pressure in the cylinder rises, the piston o rises with the end of the lever u. The pressure of the spring is such that the lever s is held stationary until the lever u moves from the top stop 3 to the lower 4, the ball 2 moving in its groove and passing over the strip i. The spring 5 is adjusted so that it is not in contact with the strip i and therefore no current passes during this motion. When the pressure rises further, the levers s, u rotate together about the pivot o, and the strip i comes in contact with the spring 5. When the pressure falls a little, the lever u passes from the stop 4 to the stop 3. The ball 2 makes contact with strips h, i and a stream of sparks results. Explosion having occurred, the pressure immediately rises and the piston o rises to its highest point, first causing the lever u to move to the stop 4 and then causing both to rotate about v. To make the device more delicate, a differential spring may be employed.