Coil Ignition : the Advantages Claimed for it.
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rpHE COAINTERCIAL motor user is -Iwell acquainted with magneto ignition, with which the great majority of vehicles are fitted as standard ignition equipment, but. of the alternative ignition system, namely, coil and battery, he probably • knows little. This latter system is, however, making headway, and mention may be made of the fact that the A.E.C. two-ton chassis and the 10 hp. Trojan are equipped with the
Remy coil-ignition system. This is a representative type, and it is noteworthy that the manufacturers' Delco-Remy, Ltd., 715, Fulham Road, London, S.W., do everything possible to snake their system easy to understand and to keep in order. For instance, they supply .a large-scale wiring chart with working instructions printed on. • There is more wiring in the case of coil ignition than with the magneto, and a .diagram is essential. The coil has certain, advantages and characteristics, and in the case of the Remy system these can be stated as follow :—(1) Easy starting, resulting. in less strain on the electrical equipment -with •consequent freedmp from battery troubles. (2) Regular 'firing at low speeds and improved power when pick-_ ing up, due to the spark intensity being as great at low speeds as at high speeds. (3) Increased engine power at high speeds, due to the'iadvance range being much greater with coil ignition than with magneto. (4) Accessibility ; the distributor can always be placed in an accessible -position. (5) Simplicity; distributor .may be driven from the camshaft or dynamo, tires dispensing with a -separate train of gears or a chain drive.' (6) Silence, due to the simple 'driving mechanism and to there being no Deduction gears in the distributor. The speed of rotation is only half that of the engine and the torque variation is negligible. (Ti Reliability ; the primary and secondary windings of the coil and the condenser are all, stationary, and are,-, therefore, unaffected by the high '
speed' of modern engines. It is sometimes said that coil ignition
depends entirely on the liatitery. The following facts may be of interest :—(1) The current required by the Remy ignition system is approximately equal, at average speeds' to that taken by one side lamp. (2) As soon as the engine is running at. any speed at all, the dynamo provides more current than the ignition consumes. Therefore, even if the battery be allowed to get into a very bad condition, there is no fear of ignition failure. (3) A .battery never fails suddenly. The driver first finds that the starter will not work, then that the lamps do not light properly, and, finally, long after that, igniti in trouble would develop. It is important that the driver switches the ignition "off " when the engine is stopped, otherwise the battery may become discharged through. the coil. On some vehicles a red lamp is fitted on the _ switchboard, which lights up when the engine is running very slowly or is
stopped with the ignition "on. This warns thedriver that. he should switch off. The carburetter throttle stop should always be set so that the engine does not stop until the ignition is switched "off." If the switch is left " on " the battery • will not he discharged for about .12 to 18 hours, and even then the engine may be started by hind if the switch iS put " off" tole 15 minutes or so before swinging the engine.