Page 10 Advertisements Column 2

Sun (Auckland), Volume III, Issue 765, 11 September 1929, Page 10

Motor Fuels Tested Remarkable Demonstration j given at Oil Company'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 than 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 heat and high compressions. It shows the advantages of the right kind. Details of the Apparatus The Midgley Bouner.g Pin Set consists of a small inVraal-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-ketted, is firmly fixed on a solid base. 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 - _ _ - 4.0 to 1 English „ _ _ _ 5.2 to 1 Continental _ _ _ 5.4 to 1 so it can be seen that any motor spirit that stands up to the. conditions existing in this trial engine, will not break 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 the engine through the generator, and which can be varied by the operator by means of a control on the instrument-board; vnile 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 combustion head, similar to a spark-plug 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 s 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 any shock or vibration (when knocking is taking place) to the pin above it. which is thus caused to “bounce.” 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 “knock-measuring” device on the instrument board. When a Knock Occurs When a knock occurs in the engine, the diaphragm is “sprung”; the pin bounces; taps the contact - arms together, closes the circuit, the red light flickers, and the knock-indicator works. The “knock-measuring” device consists of a calibrated glass 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 les3, 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 which is bound to be recorded in ultimate performance, i.e., in more, or less, gear changing or in more, or less, miles per gallon. 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 rste at which Plume burns, eliminates all kinds of knocking and ensures maximum power output. Engineers who have witnessed tests acknowledge that this inherent appotenic quality places Plume in a class by itself —a genuine knock-proof motor spirit of iacogipaJabte quality., -