GB621353A - Improved means for use in checking the timing of the ignition in an internal combustion engine - Google Patents

Abstract

621,353. Testing ignition. AUSTIN MOTOR CO., Ltd., WEAVING, J. H., and HIGHFIELD, F. W. W. Feb. 21, 1947, Nos. 5078 and 16727. [Class 7 (iv)] The invention relates to means for checking the ignition timing of internal combustion engines whereby each time the contact breaker points of the ignition system open in respect of any plug or in respect of a selected plug the voltage generated by a transformer energised as a result of the breaking of the contact breaker points is utilised to trip or control a flash of an electronic flash tube energised from a separate source of electric power, thus forming a stroboscopic device. A low tension ignition circuit consisting of battery B, contact breaker points A with a shunted condenser H, has a transformer C with two primary windings c, d connected therein. Upon each operation of the circuit breaker points A the winding c supplies impulses through a distributor, to the sparking plugs, whilst the winding d triggers an electronic flash lamp F, that is connected in parallel with a condenser G, to a high tension direct current source. The resulting flash illuminates a mark on the engine flywheel and by a stroboscopic action' enables the crank shaft angle at the moment of ignition to be read on a fixed scale. In a modification, Fig. 2, the timing of any particular plug may be ascertained by inserting in the plug lead the primary of a loose-coupled transformer J. When the plug receives an impulse it is reflected into the secondary of the transformer J and by momentarily increasing the grid voltage of a triode M connected in series with a transformer primary d across a high tension direct current source, the latter having a condenser T in parallel, causes the triode M to conduct and so supply an impulse to the transformer primary d, the secondary winding being connected to a circuit identical to the flash tube circuit in Fig. 1. In another modification for an engine which is being " motored the low tension circuit is similar to Fig. 1 except that primary winding c is dispensed with. If it is desired to check the crank shaft angle at which any particular plug would have fired, the flash tube " trigger " lead is taken through one contact of a distributer. The second Provisional Specification states that the flash tube may be dispensed with and the triode may be of the type which gives illumination when " triggered."