Electric Ignition and Lighting for Commer cial Motor Vehicles.
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Ignition troubles are now comparatively infrequent. The bogie of a few years ago has been successfully eliminated. Badly-designed ignition devices, of poor construction and material, have given place to modern magnetos. The lowtension type of magneto has rendered good service, and it is still preferred by many users whose experiences of that class of magneto have been favourable, but the hightension class is undoubtedly the one which is now employed most widely. It has won for itself the premier place among ignition systems, by means of its reliability and the fact that it is self-contained. A determined attempt was recently made by a large London motor-omnibus company, to revive the now-obsolete system of ignition in which batteries and coils, in conjunction with a commutator or high-tension distributor, are used, but, after giving the system a thorough trial, the company has discarded it in favour of high-tension magnetos.
Numerous inventors have contributed towards the success of this type of machine, and prominent amongst them are the names of Bosch, Eisemann, Fuller, Hall, Simnis and Vandervell. Both the Bosch and the Simms companies have come forward to the assistance of a largo number of users of small commercial vehicles with duplex ignition systems, which provide for easy-starting. A battery current is employed, in conjunction with the magneto armature, to produce a spark by merely " turning over " the engine. There is a considerable number of two-eylin der engines used for commercial work, and it is in order to the difficulty of starting engines of this type that the new system has been introduced. Another magneto which the Bosch Co. has recently
marketed is intended to produce two sparks: the doublespark system is attracting much attention at the present time, on account of the great increase of power which, it is stated, may be obtained by its use. The main difference between this and other magnetos is that in the double-spark machine the secondary winding is distinct from the primary. Both the ends of the secondary winding are attached to the slip ring, which detail has a divided segment instead of its being made continuous as in the machines of normal build. There are two hightension collecting brushes, and these are arranged diametrically opposite each other ; each brush is connected permanently to its respective distributor, and a safety spark-gap is arranged in parallel between the distributor and the frame. It should be pointed out that in adopting this system it is necessary that. the sparking-plugs be arranged as far apart in the cylinder as possible, so that each plug may fire an effective proportion of the gas. The Eisernann Co.'s new model provides for the automatic advancing of the spark as the speed of the engine, is increased. This alteration in the angular advance of the armature is effected by means of a centrifugallyoperated governor, the Hying weights of which transmit endwise motion to a rectangular Lima that is fitted in a tunnel; the bore of this boss has two spiral key-ways, and by these the endwise movement of the boss is converted into a rotatory movement of the armature spindle. This system dispenses with the need for the usual spark-advance lever, and its makers claim that it is far more effective than any system of hand-control could be, no matter how expert the driver may he. Both at high and low speeds, this magneto produces an equally-hot spark, thereby insuring the complete inflammation of the charge under all
conditions of running. A series of tests have been made on a 30 h.p. Mercedes engine, to which one of the magnetos was fitted, and although it may seem incredible, we are assured that the effect of this magneto has been to cause a saving of 15 per cent. in the fuel consumption. This result, it is stated, is due to the fact that the angular position of the spark is at all times dependent upon, and timed to suit., the speed of the engine. The producing company does not claim that in all cases would a saving of 15 per cent, be effected, but it is confidently asserted that a reduction of at least five per cent. may be made by the use of this automatic-advance magneto.
The Simms lit, dual magneto, a. British-made machine, is one of the best-known and most-practical of its type. This magneto has two contact breakers and is intended. for to he used in conjunction with a change-over switch ; this combination of magneto and change-over switch enables the plugs to be supplied with current either direct from the magneto or by a current which is induced in the windings of the magneto by the primary current from a battery. '1' he battery ignition is timed rather later than that of the magneto, this condition of timing being advisable and necessary for starting purposes.
In the course of the present article it would not. be possible to give anything like a complete list of the makers of electrical fittings suitable for commercialvehicle work; there are many houses which specialize in such details. Among these we may mention: Brown Bros„ Ltd., of Great Eastern Street, London, E.C. ; the United Motor Industries, Ltd., of 45-6, Poland Street., London, W.; and Messrs. C. A. Vandervell and Co., of Warple Way, Acton Vale, London, W. Brown Bros., Ltd., carries a very-large stock of ignition fittings, and is in a position to supply some hundreds of patterns of sparking plugs. We. would particularly mention the Mascot plug, which is one of the most practical that has been introduced of recent years: this plug is being manufactured by the Mascot Co., of Rugby, and its special feature is the enamel packing between the metal shell and the porcelain.
The satisfactory lighting of motor vehicles is highly important, especially if vehicles are to be operated on roads on which sharp bends are numerous and the surface is in bad condition. It is not sufficient, in some cases, to rely upon paraffin or acetylene lighting; acetylene generators require frequent attention, and on long country runs it is sometimes a matter of inconvenience. Paraffin lamps, too, have their disadvantages, and in many cases which have been brought to our notice, particularly for vehicles which are used on mail services, users are carrying a double set of lamps, one of these sets being of the ordinary paraffin type, and the other electric. For the latter class of lamp, the current is supplied either by battery or a small dynamo, such as that manufactured by Messrs. C. A. Vandervell and Ca. This dynamo, which is a development of the Leitner system, has now been reduced to a most-practical outfit, and it may be relied upon to stand up to its work under arduous conditions. In the latest type of Vandervell dynamo, regularity of output is secured by an ingenious arrangement of the field windings, and by their grouping relative to the windings of the armature. A simple form of free-wheel clutch is embodied in its construction, by means of which clutch it is possible, when the dynamo is being driven at a speed too low to supply a current to the battery, for the Former to drive the engine. Current from the battery may actually drive the armature, but in such an event the only resistance which has to be overcome is that due to the friction in the armature bearings; no driving effort is transmitted through the coupling. The maximum output from the battery under such conditions would not exceed 11ampere. This maker has produced a succinctlycompiled handbook, in which the constructional details of the C.A.V. dynamos are described, and the advantages attending the use of this system of lighting are set out. The cost of installation varies from £12 15s. up to £26 Ss. per set, according to the size and number of lamps required on the car, the installation including a dynamo, rotary controlling switch, a four-volt battery, and the requisite number of lamps. With such an equipment. there is no delay or waste of time over " lighting up; " the driver has to turn one or more switches—that is all. Its operation proceeds automatically thereafter. Nlessrs. John C. Fuller and Son have also introduced a practical and neat system of electric lighting for motor vehicles. The dynamo in this case is of the same size and shape as a magneto. It is connected in series with a magnetic cut-out and a small battery, the lamps themselves being connected in .parallel across the mains. When the dynamo is being driven at a speed too low for the generation of current, the cut-out prevents the current from the battery driving the armature. A small governor is fitted to the armature shaft, and as soon as the speed becomes sufficient for the generation of current the magnetic cot-out switch is elosed, thus coneecting the armature in series with the battery. Both these companies (Vandervell and Fuller) supply batteries and lamps suitable for use in the lighting of motor vehicles.