Patent GB-598809-A (GB)
Title: Improvements in or relating to fuel supply systems for internal combustion engines
IPC: F02D19/12
Filed: 1945-09-11
Abstract: 598,809. Spray carburetters ; regulating. NAPIER & SON, Ltd., D., and CHAMBERLIN, R. H. D. Sept. 11, 1945, No. 23398. [Classes 7 (iii) and 7 (vi)] In a supercharged engine wherein the fuel is delivered under pressure into the nose of the supercharger and anti-detonant is injected adjacent the fuel nozzle above a predetermined boost pressure and engine speed, the anti-detonant passes through a pressure regulator, and a metering device which is controlled by boost pressure and associated with supercharger speed. At a predetermined boost pressure and engine speed the capsule J and speed selector lever H close contacts J<3> and H<1> in the circuit of an electric pump E which then delivers antidetonant from a tank D, the delivery being controlled by a by-pass valve F carried by a diaphragm F<1> subject to air intake pressure. From an air-bubble separator E<3> the anti-detonant flows through a pipe E' to a pressure regulator K and through a valve K<2> and pipe E<9> to a metering device M. The diaphragm K<1> carrying the valve K<2> is subject to unmetered anti-detonant pressure on its lower side and to the metered pressure through a pipe E' on its upper-side, the spring K<8> being adjustable to produce the required metering pressure across the metering device M which comprises two valves M<6>, M<7> controlled by boost pressure acting on a capsule M<9>. The flow from the metering device at moderate speeds is solely through the valve M<6> and pipe E<10>, but when the supercharger gear-change lever O is moved to its full speed position Ob, a cock N opens a byepass pipe E" to allow additional 'flow through the valve M<7>, the total flowing by pipe E<8> and through a safety valve P to mix with fuel in chamber C prior to delivery from a nozzle A in the air intake B. The valve P is operated by oil pressure transmitted through pipes L and L<2> and acting on a piston P<6> to keep a diaphragm P<1> closed on a valve seating P<4>, the oil pressure being regulated by a doubleacting valve K<7> carried by a diaphragm K<12> subject to the pressure, of the anti-detonant in the regulator K. When no anti-detonant is flowing the valve K' closes an oil return passage L<1> and the full oil pressure keeps the valve P closed; as the pressure of the anti-detonant builds up the valve K<7> is applied to the sealing K<6>, reducing the oil pressure in the pipe L<2> and allowing the valve P to open. This reduction in oil pressure also operates through a piston R a lever R<3> carrying a stop R<8> allowing the boost control lever R<6> to be set to a higher value, and further a piston X controlling the valve W<4> of a boost-pressure operated ignition control so that the ignition is advanced as the oil pressure is reduced. The fuel, supplied from a pump through a pipe A<3>, metering orifice T, and diaphragm-controlled valve S<4>, is controlled according to speed by a centrifugal impeller A<6> in a subsidiary closed circuit A<5> setting the pressure in the chamber S<3>. When the anti-detonant starts to flow, movement of the lever R<3> to the right due to the reduced oil pressure opens a restriction U in the impeller circuit, thereby increasing the pressure in S<3> and decreasing the fuel supply, a similar decrease being caused by the closing at full speed of a restriction V connected to the supercharger gear change lever O. Specification 563,643 is referred to.