Patent GB-190808966-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: 1908-04-24
Granted: 1909-04-22
Abstract: 8966. Humphrey, H. A. April 24. [Patent of Addition to No. 2509, A.D. 1907.] Gas and like engines, igniting in. Consists in improvements in the method of igniting a gaseous mixture described in Specification No. 2509, A.D. 1907, in which the occurrence of the ignition is dependent upon the compression pressure having reached the maximum, and also in rendering the method more readily available where a magneto is employed. The small motor actuated by the gas pressure is used to store energy, the whole or a part'of which may be liberated steadily or suddenly according as a battery or a magneto is employed. The liberated energy actuates a switch mechanism which determines the formation of sparks. The pressure of the gases is communicated to the piston 3, Fig. 1, and preferably through a liquid column where the apparatus is used in connexion with a pump of the kind described in Specification No. 18,594, A.D. 1907. This piston is attached to a rod 4, which rotates an insulated pulley 9 through a band 8 attached to a spring 10. Fixed to the pulley 9 is a switch arm 13, Fig. 2, which moves over a contact 16 connected to a terminal 17. the motion of the arm being limited by stops 14, 15. The rod 4 carries a stop 21 to limit its downward movement and a stop 22 to engage the switch arms 23, 24. The battery circuit is connected up to the terminals 17, 31. In the position shown in Fig. 1, the current passes from terminals 31, through contact 28, to a switch body 33, column 35, switch body 34, and contact 26 to a terminal 32, and thence by a wire to a terminal 19, pulley 9, and arm 13 to a contact 17, thus completing the circuit and producing sparks. This occurs only once in a cycle for the following reason. As compression proceeds the piston 3 is forced up and the switch arm 13 is forced against the stop 14, after which the band 8 slips over the pulley 9 and stretches the spring 10. The switch arm passes over the contact 16 before the stop 22 allows the switch 34 tu close, so that the circuit is not completed. On further rising, the switch 34 closes. Just as the maximum, compression pressure has been reached and begins to drop slightly, the arm 13 is brought over the contact 16 and sparking occurs. The sudden rise produced by ignition causes the stop 22 to open the switch 33, the circuit having also been broken by the movement of the arm 13 to the stop 14. During expansion, the arm 13 passes to the stop 15 and the switch 33 becomes closed, the circuit being, however, still broken ; the stop 22 then opens the switch 34, so that when atmospheric pressure is reached the parts are again in the position from which they started and the circuit remains broken during the exhaust and suction strokes. The stop 22 and switches 33, 34 can be adjusted. A screw 39 ensures a small drop in pressure at the end of compression, producing ignition. A single switch consisting of a lever 42, Fig. 3, pivoted at 44 and having a double end bearing against a spring blade 47, may be employed, the lever being actuated by the stop 41 on the rod 4. The pulley 9 and band 8 may be replaced by two pulleys, one on either side of the rod 4 ; or a rack and pinion, as shown in Fig. 6, may be used, the switch arm on the disk 58 being moved by friction. The pinion is forced against the disk by a spring-loaded lever 63, the thrust being taken by a ball bearing 66. A suitable arrangement for use with a magneto machine is shown in Fig. 7. The cylinder 2 is bolted to a bracket 68 which carries a magneto 69. The lower enlarged end 89 of a rod 88 is held by two jaws 85, 86 mounted on two wheels carried by a crosshead 78 on the rod 4. The wheels are rotated by bands 83 fixed to the cylinder 2 on opposite sides of the rod 4, the other ends being spring-loaded. Pressure is admitted above the piston 3, which as compression proceeds is forced down, whereupon the jaws 85, 86 engage the rod 88, and a pin 93 engages a lever 71, thus rotating the magneto armature. When the compression pressure drops slightly, the upward movement of the rod 4 causes the jaws 85, 86 to release the rod 88, permitting springs 76, 77 to give a quick return motion and produce a spark. The spring 5 or suitable stops limit the downward motion during expansion. The jaws 85, 86 close, and then remain open until they pass the head 89. The parts remain in about the same position during the exhaust and suction strokes. In a modification of this apparatus, shown in Fig. 9, the rod 4 passes through a guide 92 and is loaded by an adjustable spring 95. A sleeve 97 slides easily on the rod 4 and is connected by toggle-links 99, 100 to a sleeve 98 fixed to the rod 4. To this latter sleeve is fastened a band 104, which passes over a pulley carrying arms 109, 112 and is secured to a hook 107. At the beginning of compression, the parts are situated as shown in Fig. 9, pivots 101, 102, 103 being in a straight line so that the movement of the sleeve 98 is transmitted to the sleeve 97, causing the magneto lever 71 to rotate as compression proceeds. During this movement, the arm 109 is pressed against a stop 110, but as soon as the compression pressure drops slightly, the pulley turns, so that the arm 112 forces the pivot 102 to the left, causing the toggles to collapse and allowing a quick return of the armature and the production of a spark. With low-tension magnetos, electro-magnetic plugs are used, but with high tension, the jump spark-plug is employed. The liquid that transmits the pressures may be used to actuate the switches, for example, as shown in Fig. 12, the liquid passes through a strainer 133 to a chamber 117 communicating with a chamber 116 by two channels, such as 118, having non-return valves. To the piston 125, working between stops 126, 127, is attached a plate 129 carrying an insulated piece of metal 131 forming part of a switch. During compression, the piston 125 is forced down and the switch 131 is opened. On a slight fall of the compression pressure, the pressure in the compartment 116 is greater than that in the chamber 117, and the piston 125 is forced against a stop 127, closing the switch 131 and producing a spark. The rod 4 operates a switch, such as that shown in Fig. 3, in series with the switch 131. No spark occurs other than at the end of the compression period. In a modification of this type of apparatus, shown in Figs. 14 and 16, the cylinder is divided into compartments 149, 150 by a partition 134 provided with a door 135. This door is hinged on a spindle 136 which carries a switch arm 138, Fig. 16, and is kept closed by springs 144, 145. During compression, the door is opened upwards, but on a slight drop in pressure, the door is forced down and closes a switch 138, producing sparks. The arm 152 closes switches corresponding to switches 33, 34, Fig. 1. The cylinders 2 are placed with their axes horizontal. As modifications, where a magneto is used, energy may be stored by compressing air or by producing a vacuum.