High Speed Internal Combustion Engines

Author : Arthur William Judge
Publisher : Theclassics.Us
ISBN 13 : 9781230859040
Total Pages : 104 pages
Book Rating : 4.8/5 (59 download)

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Download or read book High Speed Internal Combustion Engines written by Arthur William Judge and published by Theclassics.Us. This book was released on 2013-09 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1918 edition. Excerpt: ...theoretical valve diameter for a given gas velocity is 1-2 inches, actually it has to be made 1-8 inches, to allow for frictional effects through the valve, etc., for the same charge efficiency. Heating of the Charge. Although the fresh charge enters the induction pipe at atmospheric temperature, yet, by contact with the hot ports, valves, combustion chamber and piston top, it rapidly becomes heated up. This heating of the charge depends largely upon the design of the engine, that is, upon whether the charge has to pass over any appreciable amount of the hot engine surfaces before it reaches the cylinder proper. The effect of premature heating of the charge is to cause the gases (the petrol vapour and air) to expand. Further, if the exhaust products are not effectively got rid of during the previous stroke, the charge will also be heated by direct mixing and contact with the residual products. In order to afford some idea as to the effect of a hot engine in reducing the charge volume, Fig. 68, which illustrates the results of some charge measurement tests upon a four-cylinder car engine, is shown. Curve A represents the quantity of charge sucked in when the engine was motored around cold, with the valves, of course, working in the usual manner, for various engine speeds. Curve B represents the quantity of charge inducted when the engine was firing in the usual way, measured by means of the "throttle plate" method at the carburettor. It will be evident from these curves that although in both cases the quantity of charge drawn in falls off fairly rapidly with increase in the engine speed, yet about 12 per cent. more charge is drawn in when the cylinder is cold than when hot at 800 revolutions. Hopkinson f mentions the case of a...