Page 13 Advertisements Column 1

Otago Daily Times, Issue 20811, 2 September 1929, Page 13

Motor Fuels Tested Remarkable Demonstration given at Oil Cdmpany’s Laboratory A Convincing Test ' Anybody who goes to the Yarraville Installation of the Vacuum Oil Company Pty. Ltd., and sees there the Midgley Bouncing Pin apparatus testing fuels, must be convinced that there is only one spirit on the market that is outstandingly better t h a n others; and that is appotenic Plume. . - This apparatus—the only equipment of the kind in the Southern Hemisphere—proves in deeds, to the eye and to the ear, what the appotenic Plume advertising claims in words. It shows .clearly those invisible and sometimes inaudible labourings that take place beneath the bonnet of a car when it is travelling up hill, or." under “heavy load, on the wrong kind of fuel, on fuel unstable to he&t and high compressions. It shows the advantages of the right kind. Details of the Apparatus. The Midgley Bouncing Pin Set consists of a small internal-com-bustion engine; a direct-coupled electric generator; a thermostatic cooling system; an instrument and control, board; and—the bouncing pin apparatus itself. ‘ The engine, which is water-jac-lyctted, is firmly fixed on a solid I c e. A special head has been fitted, which is designed not only to admit the bouncing pin—of which more details later—but- to give the high compression of 6.7 to 1. Average compressions- obtaining in present-day cars are as follows: — American ... 4.9 to 1 English . .... 5.2 to 1 Continental .. .. 5.4 to 1 eo i$ can be seen that any motor spirit that stands up to., the conditions existing in this trial engine, will not down in any car in the world that is not a freak car. The fuel is further “burdened” by a magnetic resistance or load which is placed on Jhe . engine through the generator, and which can be varied by the operator, by means of a control on the: jnstru-ment-board; while the spark setting is on much more-than a normal “advance.” The Measurement of Knocks Now for the measurement and the comparison of knocks./ This Is the purpose of the bouncing pin. , .In a tapped orifice in the com-bustion-head, . similar to a sparkplug hole, is screwed a . drilled steel rod about seven inches in length. Through the centre of the rod, fitting closely, but free to move, goes the “pin” itself. The lower end of the pin rests on a small diaphragm, which is held in •position by a- hollow ring nut screwed against a. shoulder in the. surrounding metal. This diaphragm takes the , pressure that is generated in the combustion chamber during the firing, stroke. While it holds the compression; it transmits shock or vibration (when knocking is taking place) to' the pin above it, which it thus caused to “bounce.”. The elements of the “bouncing-pin’ The upper end ,of the pin, while at rest, touches the lower arm of - a ’pair of contact-breakers. These are normally open, and are positioned in an electric circuit which operates a red light and a. “knockmeasuring” device on the," instrument hoard. J : " When a Knack Occurs \ When a knock occurs in the engine, the diaphragm is “sprung”; the pin bounces; taps the contactarms together, closes the circuit, the . red light flickers, and the knock-indicator works. The “knock-measuring” device consists of a calibrated glas's tube filled with an acid solution, through which the same electric current that operates the light passes. The passage of the current releases a gas <in the solution, which rises in the form of bubbles to the top of the tube. This renders comparisons between the knock-frequency of two different fuels very simple. The more gas that is collected over a given period of running, the worse, from the knocking point of view, is a fuel—the less, the better. More than Human Those who have seen tests realised fully for the first time the big difference between various brands of .motor spirits that ordinary running in a car does not always reveal —but whir l is bound to be recorded in ultimate performance, i.e., in more, or less, gear changing or in more, or less, miles per gallon. •• f . The Midgley Bouncing Pin Apparatus, is more than human.. It hears what ears cannot hear, feels what is imperceptible to the human touch.- It proves very definitely the reason for that seemingly paradoxical term, the “silent knock”; and convincingly demonstrates the value to the motorist of using'a motor, spirit 'that possesses the ‘appotenic” quality which, by controlling the rate at which Plume v . 'ohrnsj- eUminates all kinds of knocking and ensures maximum ppw&r output. Engineers who have witnessed tests acknowledge that-this inher- . ? nt appotenic quality places Plume in- a class by itself—a genuine , knock-proof motor spirit of incomparable quality.