Author Description

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1922 Excerpt: ... intercepts the direct flow of air toward the open exhaust ports. 8 Furthermore, this method sets up intense eddy currents both at the intake-port edges and at the point where the deflector lug interferes with the normal course of air flow. These eddy losses are capable of absorbing the major portion of the flow energy and of abruptly lowering the high velocity of the incoming air immediately after passing the nozzle zone. 9 Such absorption of flow energy in close proximity to the intake nozzle confines the incoming charge to a body-like formation and avoids excessive intermingling with the displaced products of combustion. In case the charge is not properly deflected and made to spread out on its way through the cylinder, the incoming air tends to head directly toward the open exhaust port without displacing the hot burnt gases lying in the upper portion of the bore. The resulting deficiency in combustion air leads to low power capacity per unit of piston displacement. BABE CHARGING PRESSURES 10 The average pressure head required to inject the air charge into the power cylinder depends upon three principal factors: Fio. 3 Port-timing Diagram a The volume of precompressed air delivered to the intake port from the base chamber 6 The average inlet-port area exposed by the piston during the base delivery period c The time available for introducing the charge into the power cylinder. The average back pressure against which the discharge from the base chamber must work is largely fixed by the area and lead given to the exhaust port. The intake port should not be allowed to open until the exhaust back pressure has dropped to a value about equal to the maximum pressure in the base chamber. The various factors that control the rate of exhaust drop will be discussed...