GB597929A - Control mechanism for supercharged internal combustion engines - Google Patents

Abstract

597,929. Fluid-pressure servomotorcontrol systems. GENERAL MOTORS CORPORATION. May 19, 1944, No. 9756. Convention date, April 17, 1943. [Class 135] [Also in Group XXVII] In a variable datum boost control mechanism for supercharged internal-combustion engines in which a differential lever interconnects the throttle valve, the manually-operable pressure selection member, and the servo-mechanism actuating the throttle valve, a cam slot and follower connection provided between the servo-mechanism and the differential lever is so related to the lever fulcrum which is movable by the manually-operable pressure selection member that any given movement of the servo-mechanism produces an angular movement of said lever 'which is greater the nearer the pressure selection member is to its lowest setting. In an embodiment, the pilot's control lever is connected to a lever 31 which rotates a shaft 30 carrying a further lever 32. At the free end of the latter is pivoted a floating bellcrank lever 34, 35, the arm 34 of which is connected by a link 37 to a lever 39 controlling the throttle valve 41. The throttle is also controlled by a servo-piston 109 which is connected by a link 48 to a roller 46 movable in a cam groove 45 on the end of arm 35 of the bell-crank 34, 35 ; the roller 46 also being carried by a lever freely pivoting on the shaft 30. The automatic control comprises an evacuated spring-loaded bellows 144 subject interiorly to engine fuel intake pressure, the free ends of the two bellows being joined together and carrying the pivot point of a floating lever 84 of which the lower end actuates a piston valve controlling the flow and exhaust of pressure fluid to the servo-piston 109. Bellows 143 has a screw-and-nut connection with the casing of the device so that the loading on the bellows can be adjusted.. The other end of lever 84 is acted upon by a cam 83 which is connected by links 79, 75 to an extension 70 of lever 31 so that actuation of the pilot's control lever to alter the throttle will also alter the datum of the bellows to select the charging pressure. The point of attachment of link 75 to extension 70 is adjustable. Movement of the servo-piston 109 also adjusts the datum of the bellows as it is connected by links 55, 56 to an eccentric sleeve 60 on the shaft which carries cam 83. Specification 594,074 is referred to.