GB549710A - Improvements in or relating to charge forming devices for internal combustion engines - Google Patents

Abstract

549,710. Spray carburetters. BENDIX AVIATION CORPORATION. May 1, 1941, No: 5690. Convention date, Sept. 23, 1940. [Class 7 (iii)] A charge-forming device comprises a primary carburetter 14, Fig. 2, connected to an intake manifold 12 through an induction passage 24 provided With a throttle valve 40, and one or more secondary carburetters 16, 18 connected to the intake manifold through induction passages 24 controlled by suction-actuated throttle valves 114, 115, pivoted non-symmetrically and closed by springs 124, 126 so long as the suction in the intake manifold is less than a predetermined value. The valves 114, 115 may have a bent lip 120 to catch the airstream, as described in U.S.A. Specification 2,156,104, and the springs 124, 126 may be calibrated so that the valves open or close successively at different degrees of suction. As shown in Fig. 2, throttle valves 40 are provided in all the induction passages 24, the primary throttle being connected by an arm 44 and link 80 to a bell-crank 78 on a shaft 74 operated from an accelerator pedal or the like through a rod 70 and arm 72. The arm 84 of the bell-crank 78 is connected by a link 82 to the slotted arm 88 of a three-armed lever 90 the arm 94 of which is connected to the throttle arm 44 of the carburetter 16 by a link 96, and the arm 98 to the throttle arm 44 of the carburetter 18 by a link 100, the slotted arm 104 of a bell-crank. 106, and a link 112. These connections may be such that the carburetter throttles open successively but reach full open position at the same time. Each carburetter has an inner Venturi 30 and an idling jet 46 below the throttle, and the carburetters 1'4, 16 have economizer valves 48 actuated by means 50 to augment the fuel supply to the main fuel nozzle when the suction behind the throttle 40 is below a pre-determined value. An air choke 52 in the inlet 20 of the primary carburetter 14 is controlled by a thermostatic element 56 and by " fast idling " means comprising an adjustment screw 64 in the throttle arm 44 acting upon a cam 60 connected by a link 62 to an arm 58 on the shaft of the air choke. One or both of the carburetters 16, 18 is provided with an air-inlet choke 21 offset on a shaft 23 and having a weighted arm 25, so that it is opened by suction. In a modification, Fig. 3, in which the primary carburetter is constructed as in Fig. 2, each secondary carburetter has a single throttle valve 132 offset on a shaft 134 and opened by suction in opposition to a closing spring 136. An arm 142 on the shaft 134 is engaged by the arm 140 of a bell-crank 138 having a slot 150 engaged by a link 154 connected directly to a bell-crank such as 84, Fig. 2, so that opening of the throttle 132 is prevented in the first stage of opening the throttle of the primary carburetter. The throttles 132 of the secondary carburetters may be arranged to open simultaneously or successively. In another form, an arm such as 142 on the throttle shaft 134 is acted upon by a bell-crank connected by linkage to a diaphragm subjected on one side to the suction in the induction pipe, so that opening of the throttle is prevented until the bell-crank is withdrawn by the action of the diaphragm. In a further modification, two horizontally arranged primary carburetters and two secondary carburetters are grouped to supply a pair of manifolds, each manifold delivering to half the engine cylinders and receiving mixture from one primary and one secondary carburetter.. Opening of the throttle of each secondary carburetter is effected by suction and is delayed by a lever having a slotted connection with the manually actuated throttle lever of the corresponding primary carburetter. In a further modification, Fig. 7, three carburetters are grouped in a single unit with a common air-inlet section 300 and air valve 313, the throttles 40 and the auxiliary throttle valves 314 being controlled by means similar to that in Fig. 2.