GB541084A - Improvements in or relating to carburetting devices - Google Patents

Abstract

541,084. Spray carburetters. BENDIX AVIATION CORPORATION. May 9, 1940, No. 8385. Convention date, May 11, 1939. [Class 7 (iii)] An accelerating-pump comprises a diaphragm 110, Fig. 4, connected at the left-hand side by a passage 124 with the induction pipe 10, so that when the throttle is rapidly opened, the diaphragm 110 is moved to the right by a spring 126 thereby forcing fuel from the right-hand side 106 of the diaphragm past a valve 152 and through jet orifices 170. The valve 152 is connected to another diaphragm 140 separating two chambers 102, 104 connected together by a restricted passage 186 and supplied with fuel from a passage 182, the fuel also passing through openings 132, 134 to the right-hand side of diaphragm 110. When this diaphragm is moved to the right upon accelerating, the diaphragm 140 is also moved to the right, owing to the restruction 186, thereby opening the valve 152 until the fuel pressure has again equalized through the restriction 186. In a modified form of accelerating-pump, fuel is supplied from the passage 182 to the chamber 104, and the chambers 102 and 106 are connected together by a restricted passage, and the chambers 104 and 106 by a passage with a non-return valve. The main jets are formed by orifices 92 in a cross piece 30, the fuel being supplied to a passage 88 in the cross piece past a valve connected to a diaphragm so as to be opened by the fuel pressure. The accelerating-pump and the main jets are supplied with fuel by a pipe 32, Fig. 1, from a chamber 39 above a diaphragm 44, which controls a valve 52 admitting fuel from a pump 55 to a chamber 40 below the diaphragm, the stem 45 of the valve being connected to other diaphragms 41, 42, 43 forming chambers 37 and 38 connected respectively to an annular chamber 25 formed around a Venturi 22 in the air intake, and another annular chamber 23 communicating with the throat of a second Venturi 20. The space above the diaphragm 41 is connected to the space 40 by a passage through the stem 45. The space 25 is connected with the air inlet 18 by tubes 26, so that the difference in pressures produced in the chambers 38 and 37 is proportional to the square of the velocity of air flow, while the pressures at opposite sides of the diaphragm 44 are proportional to the square of the velocity of fuel flow, owing to a metering restriction 61 in the connecting-passage 60. In a modification, the accelerating-pump may be connected to the chamber 40, or to the pipe 57 leading from the pump 55, instead of to the chamber 39. The diaphragms may be made of silk impregnated with neoprene or other artificial rubber compound.